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College Algebra Exam 3 Material

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Page 1: College Algebra Exam 3 Material. Ordered Pair Consists of: –T–Two real numbers, –L–Listed in a specific order, –S–Separated by a comma, –E–Enclosed within

College Algebra

Exam 3 Material

Page 2: College Algebra Exam 3 Material. Ordered Pair Consists of: –T–Two real numbers, –L–Listed in a specific order, –S–Separated by a comma, –E–Enclosed within

Ordered Pair

• Consists of:– Two real numbers,– Listed in a specific order,– Separated by a comma,– Enclosed within parentheses

• Examples of different ordered pairs:(7, 2)

(2, 7)

(3, -4)

first! fromdifferent ispair ordered Second :Note

Page 3: College Algebra Exam 3 Material. Ordered Pair Consists of: –T–Two real numbers, –L–Listed in a specific order, –S–Separated by a comma, –E–Enclosed within

Coordinates of an Ordered Pair

• The first number within an ordered pair is called the “x-coordinate”

• The second number within an ordered pair is called the “y-coordinate”

• Example, given the ordered pair (5, -2)– The x-coordinate is:

5– The y-coordinate is:

-2

Page 4: College Algebra Exam 3 Material. Ordered Pair Consists of: –T–Two real numbers, –L–Listed in a specific order, –S–Separated by a comma, –E–Enclosed within

Ordered Pairs & Interval Notation

• (2, 7) can have two meanings:– It can be an ordered pair.– It can be interval notation and have the meaning of all

real numbers between 2 and 7, but not including 2 and 7.

• Context will tell the difference, just like in the meaning of certain words.

• English Example, “bow”:– ribbon decoration on a package– an instrument for shooting an arrow

Page 5: College Algebra Exam 3 Material. Ordered Pair Consists of: –T–Two real numbers, –L–Listed in a specific order, –S–Separated by a comma, –E–Enclosed within

Rectangular Coordinate System

• Consists of:– Horizontal number line called “x-axis”– Vertical number line called “y-axis”– Intersecting at the zero points of each axis in a point ,

designated as the ordered pair (0, 0), and called the “origin”

– Forms a rectangular grid that can be used to show ordered pairs as points

axisx

axisy

Page 6: College Algebra Exam 3 Material. Ordered Pair Consists of: –T–Two real numbers, –L–Listed in a specific order, –S–Separated by a comma, –E–Enclosed within

Graphing Ordered Pair as a Point

• The x-coordinate gives horizontal directions from the origin• The y-coordinate gives vertical directions from the origin• When both directions have been followed, the point is located.• Example, graph: (-2, 3)

3,2

axisx

axisy

Page 7: College Algebra Exam 3 Material. Ordered Pair Consists of: –T–Two real numbers, –L–Listed in a specific order, –S–Separated by a comma, –E–Enclosed within

Rectangular Coordinate System

• Axes divide plane into four quadrants numbered counterclockwise from upper right

• The signs of the coordinates of a point are determined by its quadrant

• I :• II :• III :• IV :

I

III

III IV ,

, ,

,

Page 8: College Algebra Exam 3 Material. Ordered Pair Consists of: –T–Two real numbers, –L–Listed in a specific order, –S–Separated by a comma, –E–Enclosed within

Distance Formula

• The “distance” between two points (x1, y1) and (x2, y2) in a rectangular coordinate system is given by the formula:

Example: Distance between (2, -1) and (-3, 4)?

x1 = 2, y1 = -1, x2 = -3, y2 = 4

212

212 yyxx d

22 1-423- d

22 55 d

25502525 d

25 d

Page 9: College Algebra Exam 3 Material. Ordered Pair Consists of: –T–Two real numbers, –L–Listed in a specific order, –S–Separated by a comma, –E–Enclosed within

Midpoint Formula

• The “midpoint” of two points is a point exactly half way between the two points

• The formula for finding the coordinates of the midpoint of two points (x1, y1) and (x2, y2) is:

• Example: Midpoint of (2, -1) and (-3, 4)?

2

yy ,

2

xx mp 2121

2

41- ,

2

3-2 mp

2

3 ,

2

1 mp

Page 10: College Algebra Exam 3 Material. Ordered Pair Consists of: –T–Two real numbers, –L–Listed in a specific order, –S–Separated by a comma, –E–Enclosed within

Homework Problems

• Section: 2.1

• Page: 192

• Problems: All: 5 – 14

• MyMathLab Assignment 35 for practice

Page 11: College Algebra Exam 3 Material. Ordered Pair Consists of: –T–Two real numbers, –L–Listed in a specific order, –S–Separated by a comma, –E–Enclosed within

Ordered Pairs as Solutions to Equations in Two Variables

• An equation in two variables, “x” and “y,” requires a pair of numbers, one for “x” and one for “y”, to form a solution

• Example: Given the equation:2x + y = 5One solution consists of the pair:x = 2 and y = 1If it is agreed that “x” will be listed first and “y” second, this solution can be shown as the ordered pair:(2, 1)

Page 12: College Algebra Exam 3 Material. Ordered Pair Consists of: –T–Two real numbers, –L–Listed in a specific order, –S–Separated by a comma, –E–Enclosed within

Ordered Pairs as Solutions to Equations in Two Variables

Given: 2x + y = 5

Complete the missing coordinate to form ordered pair solutions:

( 1, __ )

( 3, __ )

( __, 5 )

( __, -3)

How many ordered pair solutions can be found?

31

04

number infiniteAn

Page 13: College Algebra Exam 3 Material. Ordered Pair Consists of: –T–Two real numbers, –L–Listed in a specific order, –S–Separated by a comma, –E–Enclosed within

Graphs ofEquations in Two Variables

• A “graph” of an equation in two variables is a “picture” in a rectangular coordinate system of all solutions to the equation

• A graph can be constructed by “point plotting,” finding enough (x, y) pairs to establish a pattern of points and then connecting the points with a smooth curve

• If the pattern indicates that the curve should extend beyond the graph grid, an arrow is placed on the curve where it exits the grid

Page 14: College Algebra Exam 3 Material. Ordered Pair Consists of: –T–Two real numbers, –L–Listed in a specific order, –S–Separated by a comma, –E–Enclosed within

Graph: 2x + y = 5

• Find (x, y) pairs by picking a number for “x” and solving for “y”, or vice versa

• Show solutions as (x, y) pairs• Plot each point• When pattern is seen

connect with smooth curve

with arrows at both ends• Solutions: 1,2 3,1 1,3

5,0 3,4 linestraight isPattern

Page 15: College Algebra Exam 3 Material. Ordered Pair Consists of: –T–Two real numbers, –L–Listed in a specific order, –S–Separated by a comma, –E–Enclosed within

Graph:

• Find and plot solutions (using a “T-chart” helps):

x

2 xy

y0 21 32 43 5

1 12 03 14 2

pattern shaped V

Page 16: College Algebra Exam 3 Material. Ordered Pair Consists of: –T–Two real numbers, –L–Listed in a specific order, –S–Separated by a comma, –E–Enclosed within

Homework Problems

• Section: 2.1

• Page: 194

• Problems: All: 33 – 44

• MyMathLab Assignment 36 for practice

Page 17: College Algebra Exam 3 Material. Ordered Pair Consists of: –T–Two real numbers, –L–Listed in a specific order, –S–Separated by a comma, –E–Enclosed within

Graphs vs. Form of Equation

• Experience will teach us that the general shape of a graph depends on the form of the equation in two variables

• Examples related to last section:– Equations of form: Ax + By = C will always

have a straight line graph– Equation of form: y = |mx + b| will always

have a V-shaped graph

Page 18: College Algebra Exam 3 Material. Ordered Pair Consists of: –T–Two real numbers, –L–Listed in a specific order, –S–Separated by a comma, –E–Enclosed within

Center Radius Equation of Circle

• Equation of the form:

• Will always have a graph that is a circle with center:

• and radius:

222 rkyhx

kh,

r

Page 19: College Algebra Exam 3 Material. Ordered Pair Consists of: –T–Two real numbers, –L–Listed in a specific order, –S–Separated by a comma, –E–Enclosed within

Center Radius Equation

• Considering:

• What would be the equation of a circle with center (-1, 2) and radius 3?

222 rkyhx

222 321 yx

921 22 yx

Page 20: College Algebra Exam 3 Material. Ordered Pair Consists of: –T–Two real numbers, –L–Listed in a specific order, –S–Separated by a comma, –E–Enclosed within

Center Radius Equation

• Given each of the following center radius equations, find the center and the radius: 1615 22 yx

137 22 yx

742 22 yx

:Radius

:Center

:Radius

:Center

:Radius

:Center

1,5

3,7

4,2

4

1

7

Page 21: College Algebra Exam 3 Material. Ordered Pair Consists of: –T–Two real numbers, –L–Listed in a specific order, –S–Separated by a comma, –E–Enclosed within

Homework Problems

• Section: 2.1

• Page: 194

• Problems: All: 45 – 52

• MyMathLab Assignment 37 for practice

Page 22: College Algebra Exam 3 Material. Ordered Pair Consists of: –T–Two real numbers, –L–Listed in a specific order, –S–Separated by a comma, –E–Enclosed within

General Equation of a Circle

• The equation will represent a real circle, if, when put in “center-radius form”,

Example:

• Don’t know yet, if it is a “real” circle, until written:

02 r

numbersrealareeanddcwhereedycxyx ,,,022

076222 yxyx

222 rkyhx

Page 23: College Algebra Exam 3 Material. Ordered Pair Consists of: –T–Two real numbers, –L–Listed in a specific order, –S–Separated by a comma, –E–Enclosed within

Converting General Equation to Center-Radius Equation

• “Complete the Square” twice, once on “x” and once on “y” (keep both sides balanced)Example:

• The “general equation” is a “real” circle since:

• Center and radius:

0172 r

076222 yxyx762 22 yyxx

9179612 22 yyxx

1731 22 yx

173,1 rand

Page 24: College Algebra Exam 3 Material. Ordered Pair Consists of: –T–Two real numbers, –L–Listed in a specific order, –S–Separated by a comma, –E–Enclosed within

Homework Problems

• Section: 2.1

• Page: 195

• Problems: All: 57 – 64

• MyMathLab Assignment 38 for practice

• MyMathLab Quiz 2.1 due for a grade on the date of our next class meeting

Page 25: College Algebra Exam 3 Material. Ordered Pair Consists of: –T–Two real numbers, –L–Listed in a specific order, –S–Separated by a comma, –E–Enclosed within

Relation

• Relation – any set of ordered pairs

Example: M = {(-3,2), (1,0), (4,-5)}

• Domain of a Relation – set of first members (“x coordinates”)

Example: Domain M = {-3, 1, 4}

• Range of a Relation – set of all second members (“y coordinates”)

Example: Range M = {2, 0, -5}

Page 26: College Algebra Exam 3 Material. Ordered Pair Consists of: –T–Two real numbers, –L–Listed in a specific order, –S–Separated by a comma, –E–Enclosed within

Equations in Two Variables

• Considered to be relations because solutions form a set of ordered pairs

Example:

• There are an infinite number of ordered pair solutions, but some are:

)2,4(),3,3(),2,2(),1,1(),0,0( and

xy

Page 27: College Algebra Exam 3 Material. Ordered Pair Consists of: –T–Two real numbers, –L–Listed in a specific order, –S–Separated by a comma, –E–Enclosed within

Domain ofEquations in Two Variables

• Set of all x’s for which y is a real number• May help to find domain by first solving for “y”

Example:

• Easy to see that x can be anything except -1:

Domain = ,11,

xyyx 3yxyx 3

yxx 13

yx

x

1

3

Page 28: College Algebra Exam 3 Material. Ordered Pair Consists of: –T–Two real numbers, –L–Listed in a specific order, –S–Separated by a comma, –E–Enclosed within

Range ofEquations in Two Variables

• Set of all y’s for which x is a real number• May help to find range by first solving for “x”

Example:

• Easy to see that y can be anything except 3:Range = ,33,

xyyx 3yxyx 3

yyx 3

yy

x

3

Page 29: College Algebra Exam 3 Material. Ordered Pair Consists of: –T–Two real numbers, –L–Listed in a specific order, –S–Separated by a comma, –E–Enclosed within

Function

• A special relation in which each x coordinate is paired with exactly one y coordinate

Example – only one of these is a function:

R = {(2,1), (3,-5), (2,3)}

Not a Function

S = {(3,2), (1,2), (-5,3)}

FUNCTION

Page 30: College Algebra Exam 3 Material. Ordered Pair Consists of: –T–Two real numbers, –L–Listed in a specific order, –S–Separated by a comma, –E–Enclosed within

Homework Problems

• Section: 2.2

• Page: 209

• Problems: All: 5 – 15

• MyMathLab Assignment 39 for practice

Page 31: College Algebra Exam 3 Material. Ordered Pair Consists of: –T–Two real numbers, –L–Listed in a specific order, –S–Separated by a comma, –E–Enclosed within

Dependent & Independent Variables in Functions

• Since every x is paired with exactly one y, we say that “y depends on x”

• For a function defined by an equation in two variables, x is the “independent variable” and y is the “dependent variable”

Page 32: College Algebra Exam 3 Material. Ordered Pair Consists of: –T–Two real numbers, –L–Listed in a specific order, –S–Separated by a comma, –E–Enclosed within

Functions Definedby Equations in Two Variables

• To determine if an equation in two variables is a function, solve for y and consider whether one x can give more than one y – if not, it is a function

Example – only one of these is a function:

• Solve each equation for y and analyze:

12

x

y

12

x

y

Page 33: College Algebra Exam 3 Material. Ordered Pair Consists of: –T–Two real numbers, –L–Listed in a specific order, –S–Separated by a comma, –E–Enclosed within

Example Continued

12

x

y

2xy

12

x

y

xy 2

xy

!FUNCTIONyonegivesxOne

!' FunctionaNotsytwogivesxOne

Page 34: College Algebra Exam 3 Material. Ordered Pair Consists of: –T–Two real numbers, –L–Listed in a specific order, –S–Separated by a comma, –E–Enclosed within

Function Notation

• Functions represented by equations in two variables are traditionally solved for y because doing so shows how y depends on x

Example – each of these is a different function:

12 xy

132 xxy

3 xy

Page 35: College Algebra Exam 3 Material. Ordered Pair Consists of: –T–Two real numbers, –L–Listed in a specific order, –S–Separated by a comma, –E–Enclosed within

Function Notation Continued

• When working with functions it is also traditional to replace y with the symbol f(x) or some variation using a letter other than f. This gives different functions different names:

Previous Example Written in “Function Notation”

12 xxf

132 xxxg

3 xxh

Page 36: College Algebra Exam 3 Material. Ordered Pair Consists of: –T–Two real numbers, –L–Listed in a specific order, –S–Separated by a comma, –E–Enclosed within

Function Notation Continued

• Function notation “f(x)” is read as “f of x” and means “the value of y for the given x”

Example:

If:

Then:

This means that for this f function, when x is -2, y is -7

13 xxf

7161232 f

Page 37: College Algebra Exam 3 Material. Ordered Pair Consists of: –T–Two real numbers, –L–Listed in a specific order, –S–Separated by a comma, –E–Enclosed within

Graphs ofRelations and Functions

• Can be accomplished by point plotting methods already discussed

• The graph of a relation will be a function if, and only if, every vertical line intersects the graph in at most one point (VERTICAL LINE TEST)

Page 38: College Algebra Exam 3 Material. Ordered Pair Consists of: –T–Two real numbers, –L–Listed in a specific order, –S–Separated by a comma, –E–Enclosed within

Example of Vertical Line TestWhich graph represents a function?

• Above: passes vertical line test – Function• Below: fails vertical line test – Not a Function

Page 39: College Algebra Exam 3 Material. Ordered Pair Consists of: –T–Two real numbers, –L–Listed in a specific order, –S–Separated by a comma, –E–Enclosed within

Practice Using Function Notation

• Given the functions f, g and h defined as follows, and remembering that f(2) means “the value of y in the f function when x is 2”, find the value of each function for the value of “x” shown:

If

If g = {(1,3),(-2,4),(2,5)} find g(-2)

g(-2) = 4

213 ffindxxxf 71281222 3 f

Page 40: College Algebra Exam 3 Material. Ordered Pair Consists of: –T–Two real numbers, –L–Listed in a specific order, –S–Separated by a comma, –E–Enclosed within

Practice Using Function Notation

Given the graph of y = h(x),

find h(-3)h(-3) = 1

Page 41: College Algebra Exam 3 Material. Ordered Pair Consists of: –T–Two real numbers, –L–Listed in a specific order, –S–Separated by a comma, –E–Enclosed within

Determining if Equation in Two Variables is a Function

• Solve the equation for y.

• If one x gives exactly one y, it is a function.

• If it is a function, it may be written in function notation by replacing y with f(x).

Page 42: College Algebra Exam 3 Material. Ordered Pair Consists of: –T–Two real numbers, –L–Listed in a specific order, –S–Separated by a comma, –E–Enclosed within

Example

Determine if the following equation defines a function, if so, write in function notation:

This is a function since one x gives one y

0462 2 xy

642 2 xy

32 2 xy

32 2 xxf

Page 43: College Algebra Exam 3 Material. Ordered Pair Consists of: –T–Two real numbers, –L–Listed in a specific order, –S–Separated by a comma, –E–Enclosed within

Increasing, Decreasing and Constant Functions

• A function is increasing over some interval of its domain if its graph goes up as x values go from left to right within the interval

• A function is decreasing over some interval of its domain if its graph goes down as x values go from left to right within the interval

• A function is constant over some interval of its domain if its graph is flat as x values go from left to right within the interval

Page 44: College Algebra Exam 3 Material. Ordered Pair Consists of: –T–Two real numbers, –L–Listed in a specific order, –S–Separated by a comma, –E–Enclosed within

Example

• Show the “interval of the domain” where the given function,

• is increasing: • is decreasing:• is constant:

]3,2[]2,(

),3[

Page 45: College Algebra Exam 3 Material. Ordered Pair Consists of: –T–Two real numbers, –L–Listed in a specific order, –S–Separated by a comma, –E–Enclosed within

Homework Problems

• Section: 2.2

• Page: 210

• Problems: Odd: 17 – 37, 41 – 63, 69 - 77

• MyMathLab Assignment 40 for practice

• MyMathLab Quiz 2.2 due for a grade on the date of our next class meeting

Page 46: College Algebra Exam 3 Material. Ordered Pair Consists of: –T–Two real numbers, –L–Listed in a specific order, –S–Separated by a comma, –E–Enclosed within

Linear Functions

• Any function that can be written in the form:

Example: f(x) = 3x - 1

• This is called the slope intercept form of a linear function (reason for name – explained later).

• The graph of a linear function will always be a non-vertical straight line

)( numbersrealarebandmwherebmxxf

Page 47: College Algebra Exam 3 Material. Ordered Pair Consists of: –T–Two real numbers, –L–Listed in a specific order, –S–Separated by a comma, –E–Enclosed within

Graphing Linear Functions

• Find any two ordered pairs that are solutions (chose two different x’s and find corresponding y’s)

• Plot the two points in a rectangular coordinate system.

• Draw a straight line connecting the two points with arrows on both ends.

Page 48: College Algebra Exam 3 Material. Ordered Pair Consists of: –T–Two real numbers, –L–Listed in a specific order, –S–Separated by a comma, –E–Enclosed within

Graphing a Linear Function

Graph f(x) = 3x – 1

Choose two values of “x” and calculate corresponding “y” values:

f(0) = 3(0) – 1 = -1 [ordered pair: (0,-1)]

f(2) = 3(2) – 1 = 5 [ordered pair: (2, 5)]

Page 49: College Algebra Exam 3 Material. Ordered Pair Consists of: –T–Two real numbers, –L–Listed in a specific order, –S–Separated by a comma, –E–Enclosed within

Linear FunctionsWith Horizontal Line Graphs

A linear function of the form:

can be simplified to:

This means y will always be the same (y = b) no matter the value of “x”

The graph will be a horizontal line through all the points that have a “y” value of “b”

)0( mwherebmxxf

bxf FunctionConstant

Page 50: College Algebra Exam 3 Material. Ordered Pair Consists of: –T–Two real numbers, –L–Listed in a specific order, –S–Separated by a comma, –E–Enclosed within

Example of Linear FunctionWith Horizontal Line Graph

Graph f(x) = -3

(Note: this function says no matter what value “x” is, the “y” value will be -3.)

3y

Page 51: College Algebra Exam 3 Material. Ordered Pair Consists of: –T–Two real numbers, –L–Listed in a specific order, –S–Separated by a comma, –E–Enclosed within

Homework Problems

• Section: 2.3

• Page: 221

• Problems: All: 7 – 18

• MyMathLab Assignment 41 for practice

Page 52: College Algebra Exam 3 Material. Ordered Pair Consists of: –T–Two real numbers, –L–Listed in a specific order, –S–Separated by a comma, –E–Enclosed within

Linear Relation

• A first degree polynomial equation in two variablesExamples:

• Standard form of a linear relation:

First example is in Standard Form (A=2, B=-3, C=6)Rest can be put in standard form, if desiredLast example is in standard form of a linear function

632 yxyx 48 3

2

1 xy

RelationLinear of Form Standard

FunctionLinear of Intercept) (Slope Form Standard

CByAx

Page 53: College Algebra Exam 3 Material. Ordered Pair Consists of: –T–Two real numbers, –L–Listed in a specific order, –S–Separated by a comma, –E–Enclosed within

Facts About Linear Relations

• Every linear relation,

is a linear function, can (by solving for y) be written in the form:

except when B = 0 (y term is missing)

CByAx

bmxxf

Page 54: College Algebra Exam 3 Material. Ordered Pair Consists of: –T–Two real numbers, –L–Listed in a specific order, –S–Separated by a comma, –E–Enclosed within

Example

• Write the linear relation in the standard form of a linear function:

432 yx

423 xy

3

4

3

2 xy

3

4

3

2 xxf

Page 55: College Algebra Exam 3 Material. Ordered Pair Consists of: –T–Two real numbers, –L–Listed in a specific order, –S–Separated by a comma, –E–Enclosed within

Facts About Linear Relations

• If a linear relation,

has B = 0 (the y term is missing), the relation is not a linear function, and it’s equation takes the form:

This equation has as solutions all the ordered pairs that have an x value of n (y can be any number) and its graph will be a vertical line.

CByAx

)(0 numberaxnxorCyAx

Page 56: College Algebra Exam 3 Material. Ordered Pair Consists of: –T–Two real numbers, –L–Listed in a specific order, –S–Separated by a comma, –E–Enclosed within

Example of Linear Relation with Vertical Line Graph

• Consider the linear relation:

• It can be written in the form:

• Two solutions are:

• Fails vertical line test -Not a linear function

4x

401 yx

2,45,4 and

4x

Page 57: College Algebra Exam 3 Material. Ordered Pair Consists of: –T–Two real numbers, –L–Listed in a specific order, –S–Separated by a comma, –E–Enclosed within

Homework Problems

• Section: 2.3

• Page: 221

• Problems: All: 19 – 28

• MyMathLab Assignment 42 for practice

Page 58: College Algebra Exam 3 Material. Ordered Pair Consists of: –T–Two real numbers, –L–Listed in a specific order, –S–Separated by a comma, –E–Enclosed within

Slope of a Line

• The slope, m, of a line is defined to be the ratio of the amount of vertical movement (rise) to the amount of horizontal movement (run) required to get from one point to another

rise

run

run

risemslope ,

negative? as described be line thisof slope theWhy would m-

run

rise

Page 59: College Algebra Exam 3 Material. Ordered Pair Consists of: –T–Two real numbers, –L–Listed in a specific order, –S–Separated by a comma, –E–Enclosed within

Slope of a Line Formula

• Given two points on a line, (x1, y1) and (x2, y2), the slope, m, can be calculated from the formula:

For a horizontal line y1 = y2 , so the slope of a horizontal line is always: ___

For a vertical line x1 = x2 , so the slope of a horizontal line is always: _________

run

rise

xx

yym

12

12

0

Undefined

Page 60: College Algebra Exam 3 Material. Ordered Pair Consists of: –T–Two real numbers, –L–Listed in a specific order, –S–Separated by a comma, –E–Enclosed within

Calculating Slope of a Line

• Find two points on the line and substitute into the formula

• Example: Find the slope of:

If x = 0, then y = ,

If y = 0, then x = ,

rise = 2, run = 3

3

2

03

20

m

632 yx2 2,0 3 0,3

:ispoint resulting:ispoint resulting

Page 61: College Algebra Exam 3 Material. Ordered Pair Consists of: –T–Two real numbers, –L–Listed in a specific order, –S–Separated by a comma, –E–Enclosed within

Homework Problems

• Section: 2.3

• Page: 222

• Problems: All: 35 – 42

• MyMathLab Assignment 43 for practice

Page 62: College Algebra Exam 3 Material. Ordered Pair Consists of: –T–Two real numbers, –L–Listed in a specific order, –S–Separated by a comma, –E–Enclosed within

Graphing a Line Given a Point and a Slope

• Given a point and a slope, m:– Plot the point– From the point, rise and run, according to the

value of m, to plot a second point– Connect the two points with a straight line with

arrows at both ends

1,1 yx

2,2 yx

1,1 yx

Page 63: College Algebra Exam 3 Material. Ordered Pair Consists of: –T–Two real numbers, –L–Listed in a specific order, –S–Separated by a comma, –E–Enclosed within

Example: Graph line through (-2, 1) with slope -2/3

Page 64: College Algebra Exam 3 Material. Ordered Pair Consists of: –T–Two real numbers, –L–Listed in a specific order, –S–Separated by a comma, –E–Enclosed within

Calculating Slope and y-intercept by “Solving for y”

• When a linear relation in two variables is solved for y it takes the form:where “m” is the slope, and “b” is the y-intercept

• In a previous example we used the slope formula to calculate slope: Calculating Slope of a Line A new approach is to find slope by solving for y:

What is “m”?

What is “b”?

bmxxforbmxy

632 yx623 xy

23

2 xy3

2

2

intercept"-y" therevealing ofbenefit added thegives and

formula theas slopefor valuesame gives y""for Solving

Page 65: College Algebra Exam 3 Material. Ordered Pair Consists of: –T–Two real numbers, –L–Listed in a specific order, –S–Separated by a comma, –E–Enclosed within

Graphing a Line inSlope-Intercept Form

• Write the equation in slope-intercept form

• Identify the y-intercept, b, and slope, m• Plot the y-intercept on the graph• From y-intercept, “rise” and “run” to

another point according to the ratio, m• Connect the points with a straight line

with arrows on each end

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Example of Graphing a Line Written in Slope Intercept Form

• Graph:

y intercept is: 1, slope is:

Plot y intercept

From there rise -2, run 3 and plot

Connect points with a line

13

2 xy

3

2

Page 67: College Algebra Exam 3 Material. Ordered Pair Consists of: –T–Two real numbers, –L–Listed in a specific order, –S–Separated by a comma, –E–Enclosed within

Homework Problems

• Section: 2.3

• Page: 222

• Problems: All: 45 – 58

• MyMathLab Assignment 44 for practice

• MyMathLab Quiz 2.3 is due for a grade on the date of our next class meeting

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Equations with Line GraphsRelationLinear of Form StandardCByAx

Function)(Constant Line Horizontal a isGraph - Case Specialny

FunctionLinear of FormIntercept Slope)0( mbmxy

Function) a(Not Line Vertical a isGraph - Case Specialnx

Page 69: College Algebra Exam 3 Material. Ordered Pair Consists of: –T–Two real numbers, –L–Listed in a specific order, –S–Separated by a comma, –E–Enclosed within

Point-Slope Equation of a Line

• Given a point (x1, y1) and a slope, m, the equation of the line through that point with that slope is:

y – y1 = m(x – x1)

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Using Point Slope Equation

• Write the slope intercept equation of the line through (5, -1) with slope, m = -4/3

11 xxmyy

53

41 xy

3

20

3

41 xy

3

17

3

4 xy

Page 71: College Algebra Exam 3 Material. Ordered Pair Consists of: –T–Two real numbers, –L–Listed in a specific order, –S–Separated by a comma, –E–Enclosed within

Homework Problems

• Section: 2.4

• Page: 236

• Problems: All: 1 – 22

• MyMathLab Assignment 45 for practice

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Parallel and Perpendicular Lines

• Two lines are “parallel” if they have the same slope, but different y-intercepts

• Two lines are “perpendicular” if they have slopes that are “negative reciprocals”

• Examples of slopes that are negative reciprocals:

3

2

2

3

55

1

11

Page 73: College Algebra Exam 3 Material. Ordered Pair Consists of: –T–Two real numbers, –L–Listed in a specific order, –S–Separated by a comma, –E–Enclosed within

Application Problem Involving Perpendicular Lines

• Write the slope intercept equation of a line that goes through the point (-1, 5) that is perpendicular to the line: x + 2y = 4

• First find slope of the line: x + 2y = 4 by solving for y: y = (-1/2)x + 2This line has slope, m = -1/2The perpendicular slope, m = 2Now use point-slope equation to write equation of line through (-1, 5) with slope 2:y – 5 = 2(x + 1)y = 2x + 7

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Homework Problems

• Section: 2.4

• Page: 237

• Problems: All: 27 – 42

• MyMathLab Assignment 46 for practice

• MyMathLab Quiz 2.4 is due for a grade on the date of our next class meeting

Page 75: College Algebra Exam 3 Material. Ordered Pair Consists of: –T–Two real numbers, –L–Listed in a specific order, –S–Separated by a comma, –E–Enclosed within

Basic Function Graphs

• The most basic functions include:• Identity function:• Squaring function:• Cubing function:• Square root function:• Cube root function:• Absolute value function:• Greatest integer function:

3)( xxf

2)( xxf xxf )(

xxf )(3)( xxf

xxf )(

xxf )(

Page 76: College Algebra Exam 3 Material. Ordered Pair Consists of: –T–Two real numbers, –L–Listed in a specific order, –S–Separated by a comma, –E–Enclosed within

Identify Function:

• Note: This is the slope intercept form of the linear function f(x) = mx + b, with m = 1 and b = 0

xfx00

11

xxf )(

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Squaring Function:

• Note: This is a special case of the “quadratic function” that will be discussed later

xfx

2)( xxf

2101

2

0

4

4

1

1

Page 78: College Algebra Exam 3 Material. Ordered Pair Consists of: –T–Two real numbers, –L–Listed in a specific order, –S–Separated by a comma, –E–Enclosed within

Cubing Function:

xfx2101

2

0

1

1

3)( xxf

8

8

Page 79: College Algebra Exam 3 Material. Ordered Pair Consists of: –T–Two real numbers, –L–Listed in a specific order, –S–Separated by a comma, –E–Enclosed within

Square Root Function:

• Note: This is the first of the basic functions to have a restricted domain:

xfx

xxf )(

),0[

0 011

4 29 3

Page 80: College Algebra Exam 3 Material. Ordered Pair Consists of: –T–Two real numbers, –L–Listed in a specific order, –S–Separated by a comma, –E–Enclosed within

Cube Root Function:

• Does this function have a restricted domain like the last one?

xfx

3)( xxf

, NO,

8 21

01

1018 2

Page 81: College Algebra Exam 3 Material. Ordered Pair Consists of: –T–Two real numbers, –L–Listed in a specific order, –S–Separated by a comma, –E–Enclosed within

Absolute Value Function:

xfx4422

2

4

002

4

xxf )(

Page 82: College Algebra Exam 3 Material. Ordered Pair Consists of: –T–Two real numbers, –L–Listed in a specific order, –S–Separated by a comma, –E–Enclosed within

Greatest Integer Function:

• Note: This function pairs every real number x with the “greatest integer less than or equal to x”

• There is no restriction on the domain, but the range will be the set of all integers

xfx

xxf )(

x xf

2

7.2

2.3

9.3

4

1.4

5

2

3

4

4

4

5

5

9.0

3.0

0

1.0

7.0

1

3.1

0

0

0

1

1

1

2

Function" Step"

Include

Includet Don'

Page 83: College Algebra Exam 3 Material. Ordered Pair Consists of: –T–Two real numbers, –L–Listed in a specific order, –S–Separated by a comma, –E–Enclosed within

Homework Problems

• Section: 2.5

• Page: 249

• Problems: All: 7 – 14, 16, 33 – 35

• MyMathLab Assignment 47 for practice

Page 84: College Algebra Exam 3 Material. Ordered Pair Consists of: –T–Two real numbers, –L–Listed in a specific order, –S–Separated by a comma, –E–Enclosed within

Continuity of Functions

• A function is “continuous over some interval of its domain” if, over that interval, its graph can be drawn from one end to the other, using a pencil, without lifting the pencil from the paper

• The points where a function is not continuous are called “points of discontinuity”

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Give domain and intervals of domain where these are

continuous: ,-

,- ) [0, ,-

,-

) [0, :Continuous

:Domain

:Continuous

:Domain

:Continuous

:Domain

Page 86: College Algebra Exam 3 Material. Ordered Pair Consists of: –T–Two real numbers, –L–Listed in a specific order, –S–Separated by a comma, –E–Enclosed within

This function is continuous over only short intervals of the domain. Give

domain and the points of discontinuity.

:itydiscontinu of Points

:Domain ) ,(-

integer.every at occur

Page 87: College Algebra Exam 3 Material. Ordered Pair Consists of: –T–Two real numbers, –L–Listed in a specific order, –S–Separated by a comma, –E–Enclosed within

Describe domain and the intervals of the domain where

the function is continuous:

:intervals in these Continuous

) (2,1] (-2,2- ,5- :Domain

) (2,1] (-2,2)- ,5[-

Page 88: College Algebra Exam 3 Material. Ordered Pair Consists of: –T–Two real numbers, –L–Listed in a specific order, –S–Separated by a comma, –E–Enclosed within

Homework Problems

• Section: 2.5

• Page: 249

• Problems: All: 1 – 6, 15

• MyMathLab Assignment 48 for practice

Page 89: College Algebra Exam 3 Material. Ordered Pair Consists of: –T–Two real numbers, –L–Listed in a specific order, –S–Separated by a comma, –E–Enclosed within

Piecewise Defined Functions

• These are functions that are defined by different rules for different intervals of their domain

• Example:

• To evaluate the function for specific values of “x”, use the formula for the interval that contains “x”

-2 xif

2 if 2

x

xxf(x)

5f 2f5 4

3f 3

2f 4

0f 0

Page 90: College Algebra Exam 3 Material. Ordered Pair Consists of: –T–Two real numbers, –L–Listed in a specific order, –S–Separated by a comma, –E–Enclosed within

GraphingPiecewise Defined Functions

• Plot enough points in each interval of the domain to establish the pattern in each interval

-2 xif

2 if 2

x

xxf(x)

:Graph

:Domain

:Range

:ityDiscontinu ofPoint

) ,(- ) 0,[)2,( 2x

:determined werepairs following theslide previous theFrom

4,2,0,0,4,2,3,3,5,5

Page 91: College Algebra Exam 3 Material. Ordered Pair Consists of: –T–Two real numbers, –L–Listed in a specific order, –S–Separated by a comma, –E–Enclosed within

Homework Problems

• Section: 2.5

• Page: 250

• Problems: Odd: 17 – 31

• MyMathLab Assignment 49 for practice

• MyMathLab Quiz 2.5 is due for a grade on the date of our next class meeting

Page 92: College Algebra Exam 3 Material. Ordered Pair Consists of: –T–Two real numbers, –L–Listed in a specific order, –S–Separated by a comma, –E–Enclosed within

Transformations of Graphs

• Given a basic function graph, or any other, specific changes in the definition of the function lead to very similar graphs as follows:

• Given the graph of y = f(x), and assuming that h and v are positive, each of the following alterations to the function modifies the original graph as shown:

• y = - f(x)– Reflects original graph over x axis

• y = af(x)– Vertically stretches or squeezes original graph by a

factor of a

Page 93: College Algebra Exam 3 Material. Ordered Pair Consists of: –T–Two real numbers, –L–Listed in a specific order, –S–Separated by a comma, –E–Enclosed within

Transformations of Graphs

• y = f(x – h)– Horizontally translates the graph h units to the

right

• y = f(x + h)– Horizontally translates the graph h units to the

left

Page 94: College Algebra Exam 3 Material. Ordered Pair Consists of: –T–Two real numbers, –L–Listed in a specific order, –S–Separated by a comma, –E–Enclosed within

Transformations of Graphs

• y = f(x) – v– Vertically translates the graph v units

downward

• y = f(x) + v– Vertically translates the graph v units upward

Page 95: College Algebra Exam 3 Material. Ordered Pair Consists of: –T–Two real numbers, –L–Listed in a specific order, –S–Separated by a comma, –E–Enclosed within

Transformations of Graphs

• y = af(x – h) + v– Has the combination of effects previously

discussed – moves original graph horizontally right h units, shifts vertically upward v units and vertically stretches or squeezes by a factor of a

Page 96: College Algebra Exam 3 Material. Ordered Pair Consists of: –T–Two real numbers, –L–Listed in a specific order, –S–Separated by a comma, –E–Enclosed within

Example of Graph Transformations

xxf )(

Page 97: College Algebra Exam 3 Material. Ordered Pair Consists of: –T–Two real numbers, –L–Listed in a specific order, –S–Separated by a comma, –E–Enclosed within

Example of Graph Transformations

• How does this transform the graph?

• Should reflect graph across the x axis:

xxf )(

blackin shown )( xxf

Page 98: College Algebra Exam 3 Material. Ordered Pair Consists of: –T–Two real numbers, –L–Listed in a specific order, –S–Separated by a comma, –E–Enclosed within

Example of Graph Transformations

• How does this transform the graph?

• Vertically stretches by a factor of 2:

xxf 2)(

blackin shown )( xxf

Page 99: College Algebra Exam 3 Material. Ordered Pair Consists of: –T–Two real numbers, –L–Listed in a specific order, –S–Separated by a comma, –E–Enclosed within

Example of Graph Transformations

• How does this transform the graph?

• Vertically squeezes by a factor of ½ :

xxf2

1)(

blackin shown )( xxf

Page 100: College Algebra Exam 3 Material. Ordered Pair Consists of: –T–Two real numbers, –L–Listed in a specific order, –S–Separated by a comma, –E–Enclosed within

Example of Graph Transformations

• How does this transform the graph?

• Moves it horizontally one unit to the right:

1)( xxf

blackin shown )( xxf

Page 101: College Algebra Exam 3 Material. Ordered Pair Consists of: –T–Two real numbers, –L–Listed in a specific order, –S–Separated by a comma, –E–Enclosed within

Example of Graph Transformations

• How does this transform the graph?

• Translates it vertically down 4 units:

4)( xxf

blackin shown )( xxf

Page 102: College Algebra Exam 3 Material. Ordered Pair Consists of: –T–Two real numbers, –L–Listed in a specific order, –S–Separated by a comma, –E–Enclosed within

Example of Graph Transformations

• How does this transform the graph?

• Horizontally translates 1 unit left

• Vertically translates 3 units down

• Vertically stretches by 2:

312)( xxf

blackin shown )( xxf

Page 103: College Algebra Exam 3 Material. Ordered Pair Consists of: –T–Two real numbers, –L–Listed in a specific order, –S–Separated by a comma, –E–Enclosed within

Homework Problems

• Section: 2.6

• Page: 264

• Problems: All: 1 – 3, Odd: 5 – 11, 33 – 47

• MyMathLab Assignment 50 for practice

Page 104: College Algebra Exam 3 Material. Ordered Pair Consists of: –T–Two real numbers, –L–Listed in a specific order, –S–Separated by a comma, –E–Enclosed within

Even Functions

• A function f(x) is “even” if f(-x) = f(x) for every x in the domain

• Test to determine if a function is even:If substituting “–x” for “x” makes f(-x) = f(x), the function is “even”

• Even functions have graphs that are symmetric with respect to the y-axis– every line perpendicular to the y-axis that intersects

the graph at a distance of “d” from the y-axis will also intersect the graph at a distance of “d” on the other side of the y-axis

Page 105: College Algebra Exam 3 Material. Ordered Pair Consists of: –T–Two real numbers, –L–Listed in a specific order, –S–Separated by a comma, –E–Enclosed within

Determine if f(x) = x2 is even:2)( :Given xxf

)( xf 2x 2x )(xf function! EVEN

:axis-y respect to with Symmetric

Page 106: College Algebra Exam 3 Material. Ordered Pair Consists of: –T–Two real numbers, –L–Listed in a specific order, –S–Separated by a comma, –E–Enclosed within

Odd Functions

• A function f(x) is “odd” if f(-x) = - f(x) for every x in the domain

• Test to determine if a function is odd:If substituting “–x” for “x” makes f(-x) = - f(x), the function is “odd”

• Odd functions have graphs that are symmetric with respect to the origin– every line through the origin that intersects the graph

at a distance of “d” on one side of the origin will also intersect the graph at a distance of “d” on the other side of the origin

Page 107: College Algebra Exam 3 Material. Ordered Pair Consists of: –T–Two real numbers, –L–Listed in a specific order, –S–Separated by a comma, –E–Enclosed within

Determine if f(x) = x3 is odd:3)( :Given xxf

)( xf 3x 3x )(xf function! ODD

:origin respect to with Symmetric

Page 108: College Algebra Exam 3 Material. Ordered Pair Consists of: –T–Two real numbers, –L–Listed in a specific order, –S–Separated by a comma, –E–Enclosed within

Homework Problems

• Section: 2.6

• Page: 265

• Problems: All: 19 – 30

• MyMathLab Assignment 51 for practice

• MyMathLab Quiz 2.6 is due for a grade on the date of our next class meeting

Page 109: College Algebra Exam 3 Material. Ordered Pair Consists of: –T–Two real numbers, –L–Listed in a specific order, –S–Separated by a comma, –E–Enclosed within

Resultant Functions from Operations on Functions

• Given functions f and g we can define sum, difference, product and quotient functions as follows:

• Sum function:

• Difference function:

• Product function:

• Quotient function:

xgxfxgf

xgxfxgf

xgxfxfg

0 ,

xg

xg

xfx

g

f

Page 110: College Algebra Exam 3 Material. Ordered Pair Consists of: –T–Two real numbers, –L–Listed in a specific order, –S–Separated by a comma, –E–Enclosed within

Domains of Sum, Difference, Product and Quotient Functions

• The domain of each of these functions is the intersection of their individual domains, with the exception that for the quotient function, those values of x are excluded for which g(x) = 0

• Note: Domains must be determined from individual functions not from looking only at the resultant function

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Examples of Operations on Functions

• Given:

• Find definition and domain of:

xgf

xgf

xfg

x

g

f

xxgandx

xf

)( 1

1)(

: Domain

:Domain

g

f ,11, ,0

:Domain Domain gf ,11,0

xx

1

1

xx

1

1

1xx

Domain

Domain

Domain

Domain ,11,0 1

1

xx

,11,0

,11,0

,11,0

Page 112: College Algebra Exam 3 Material. Ordered Pair Consists of: –T–Two real numbers, –L–Listed in a specific order, –S–Separated by a comma, –E–Enclosed within

Examples of Operations on Functions

• Given information from previous slide:

xgf

xgf

xfg

x

g

f

xx

1

1

xx

1

1

1xx

1

1

xx

4gf

4fg

4

g

f

4gf3

7

3

5

3

2

6

1

Page 113: College Algebra Exam 3 Material. Ordered Pair Consists of: –T–Two real numbers, –L–Listed in a specific order, –S–Separated by a comma, –E–Enclosed within

Example: Determining Domain

• As previously noted: Domains must be determined from individual functions not from looking only at the resultant function

• Example:

.

x

xf1

2

x

xg1

2

:Domain f

:Domain g

,0

,0

xgf 4 :Domain g ,0

,- isdomain t think thayou wouldfunction resultant at theonly look you If

NOT

Page 114: College Algebra Exam 3 Material. Ordered Pair Consists of: –T–Two real numbers, –L–Listed in a specific order, –S–Separated by a comma, –E–Enclosed within

Homework Problems

• Section: 2.7

• Page: 276

• Problems: All: 9 – 14

• MyMathLab Assignment 52 for practice

Page 115: College Algebra Exam 3 Material. Ordered Pair Consists of: –T–Two real numbers, –L–Listed in a specific order, –S–Separated by a comma, –E–Enclosed within

Evaluating Resultant Functions from Graphs

xfy

xgy

1gf

2

g

f

2fg

0gf

2 11 gf

2

2

g

f3

22 gf 9

00 gf 0

Page 116: College Algebra Exam 3 Material. Ordered Pair Consists of: –T–Two real numbers, –L–Listed in a specific order, –S–Separated by a comma, –E–Enclosed within

Homework Problems

• Section: 2.7

• Page: 277

• Problems: All: 23 – 26

• MyMathLab Assignment 53 for practice

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Difference Quotient

• If (x, f(x)) represents a point on the graph of y = f(x) and “h” is a positive number, then (x+h, f(x+h)) is a second point on the graph and, from the slope formula, the slope of the line joining these points is:

12

12

xx

yym

xhx

xfhxf )()(

h

xfhxf )()(

Calculus)in (ImportantQuotient Difference

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Finding Difference Quotient

Given find difference quotient xxxf 26h

xfhxf )()(

hxhxhxf 26 hxhxhx 22 26

h

xxhxhxhx

h

xfhxf 222 66126)()(

h

xxhxhxhx 222 66126

h

hhxh 2612

h

hxh 16121612 hx

Page 119: College Algebra Exam 3 Material. Ordered Pair Consists of: –T–Two real numbers, –L–Listed in a specific order, –S–Separated by a comma, –E–Enclosed within

Homework Problems

• Section: 2.7

• Page: 278

• Problems: Odd: 33 – 39

• MyMathLab Assignment 54 for practice

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Composition of Functions

• Given two functions f(x) and g(x), a third function, called the composition function:

may be defined as:

• The domain of the composition function is the set of all “x” in the domain of g , such that g(x) is in the domain of f

• Note: In general:

)(xgf

xgfxgf )(

)()( xfgxgf

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Example of FormingComposite Functions

• Given:• Find:

32 2 xxgandxxf

)(xgf

xgfxgf )(

3 xf

232 x

962 2 xx

18122 2 xx )(xgf

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Example to Show that Composition is Not Commutative• Given:• Find:

• Not the same!

32 2 xxgandxxf

)(xfg

xfgxfg )(

22xg

32 2 x )(xfg

Page 123: College Algebra Exam 3 Material. Ordered Pair Consists of: –T–Two real numbers, –L–Listed in a specific order, –S–Separated by a comma, –E–Enclosed within

Homework Problems

• Section: 2.7

• Page: 278

• Problems: Odd: 41 – 53, 57 – 63

• MyMathLab Assignment 55 for practice

• MyMathLab Quiz 2.7 is due for a grade on the date of our next class meeting