pg. 323/361 homework pg. 362 #39 – 47 odd, 51, 52 memorize trig. info #2qiv#4qiii#6qiii...

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Pg. 323/361 Homework • Pg. 362 #39 – 47 odd, 51, 52 Memorize Trig. Info • #2 QIV #4 QIII #6 QIII • #8 -250° #10 470° • #12 338°, 698°, -382°, -742° #14 210°, 570°, -510°, -870° • #16 11π/4, -5π/2 #18 29π/6, -19π/6 • #20 π/4, 9π/4, -15π/4, -23π/4 #22 67°, 157° • #24 78°, 168° #26 5π/12, 11π/12 #28 π/14, 4π/7 • #30 90°, π/2 #32 135°, 3π/4 #34 0°, 0, 2π • #36 -120°, -2π/3 #38 -600°, -10π/3 #40 -1260°, -7π • #42 π/3 #44 7π/6 #46 11π/6 • #48 59π/90 #50 249π/180 #52 810/π • #1 #2 #3 8/7 • #4 7/8 #5 #6 • #7 • #8 11/15 #9 #10 • #11 #12 #13 15/11 8 113 7 113 113 7 113 8 2 26 15 15 2 26 2 26 11 11 2 26 113 113 7 8 7 8 , , , , , 8 7 8 7 113 113

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Page 1: Pg. 323/361 Homework Pg. 362 #39 – 47 odd, 51, 52 Memorize Trig. Info #2QIV#4QIII#6QIII #8-250°#10470° #12338°, 698°, -382°, -742°#14210°, 570°, -510°,

Pg. 323/361 Homework• Pg. 362 #39 – 47 odd, 51, 52

Memorize Trig. Info

• #2 QIV #4 QIII #6 QIII• #8 -250° #10 470°• #12 338°, 698°, -382°, -742° #14 210°, 570°, -510°, -870°• #16 11π/4, -5π/2 #18 29π/6, -19π/6• #20 π/4, 9π/4, -15π/4, -23π/4 #22 67°, 157°• #24 78°, 168° #26 5π/12, 11π/12 #28 π/14, 4π/7• #30 90°, π/2 #32 135°, 3π/4 #34 0°, 0, 2π• #36 -120°, -2π/3 #38 -600°, -10π/3 #40 -1260°, -7π• #42 π/3 #44 7π/6 #46 11π/6• #48 59π/90 #50 249π/180 #52 810/π• #1 #2 #3 8/7• #4 7/8 #5 #6• #7• #8 11/15 #9 #10• #11 #12 #13 15/11

8113

7113

1137

1138

2 2615

152 26

2 2611

112 26

113 1137 8 7 8, , , , ,8 7 8 7113 113

Page 2: Pg. 323/361 Homework Pg. 362 #39 – 47 odd, 51, 52 Memorize Trig. Info #2QIV#4QIII#6QIII #8-250°#10470° #12338°, 698°, -382°, -742°#14210°, 570°, -510°,

6.5 Trig Functions of an Acute Angle

Trig Functions• The six trig functions of any

angle 0° < Ɵ < 90° are defined as follows:

• Also, we know that from the basic three trig functions:

sin cot

cos sec

tan csc

opp adj

hyp opp

adj hyp

hyp adj

opp hyp

adj opp

1cot

tan1

seccos1

cscsin

Page 3: Pg. 323/361 Homework Pg. 362 #39 – 47 odd, 51, 52 Memorize Trig. Info #2QIV#4QIII#6QIII #8-250°#10470° #12338°, 698°, -382°, -742°#14210°, 570°, -510°,

6.5 Trig Functions of an Acute Angle

Triangle Trig• We use right triangles

because they allow us to use the Pythagorean Theorem, which makes solving a much easier process!

• Because 30°, 45° and 60° occur frequently, we will learn and memorize those triangles!!

• If c = 2, determine the lengths of a and b and find the six trig values at 30° and 60°.

Page 4: Pg. 323/361 Homework Pg. 362 #39 – 47 odd, 51, 52 Memorize Trig. Info #2QIV#4QIII#6QIII #8-250°#10470° #12338°, 698°, -382°, -742°#14210°, 570°, -510°,

6.5 Trig Functions of an Acute Angle

More Trig Triangles• If a = 1, determine the

length of c and find the six trig values.

Cofunctions of Complementary Angles

• If Ɵ is any acute trig angle, a trig function value of Ɵ is equal to the cofunction of the complement of Ɵ, as follows:

sin cos cot tan2 2

cos sin sec csc2 2

tan cot csc sec2 2

Page 5: Pg. 323/361 Homework Pg. 362 #39 – 47 odd, 51, 52 Memorize Trig. Info #2QIV#4QIII#6QIII #8-250°#10470° #12338°, 698°, -382°, -742°#14210°, 570°, -510°,

6.5 Trig Functions of an Acute Angle

Example:• Show that

are cofunctions. • Let Ɵ be an acute angle

such that sin Ɵ = 5/6. Find all the trig functions of Ɵ.

• One angle of a right triangle measures 38°, and the hypotenuse has length of 17. Find the measures of the remaining sides.

sin cos2

Page 6: Pg. 323/361 Homework Pg. 362 #39 – 47 odd, 51, 52 Memorize Trig. Info #2QIV#4QIII#6QIII #8-250°#10470° #12338°, 698°, -382°, -742°#14210°, 570°, -510°,

6.5 Trig Functions of an Acute Angle

Example:• They hypotenuse and one

leg of a triangle measure 12 and 7 respectively. Find the measure of angle Ɵ formed by these two sides.

Trig Functions of Any Angle• Let Ɵ be an angle in

standard position, P(x, y) a point other than the origin on the terminal side of P, and r = The six trig values of Ɵ are defined as follows:sin cos tan

sec csc cot

y x y

r r xr r x

x y y

2 2x y

Page 7: Pg. 323/361 Homework Pg. 362 #39 – 47 odd, 51, 52 Memorize Trig. Info #2QIV#4QIII#6QIII #8-250°#10470° #12338°, 698°, -382°, -742°#14210°, 570°, -510°,

6.5 Trig Functions of an Acute Angle

Example:• Find the values of the six

trig functions at an angle Ɵ in standard form with point P(4, 7) on its terminal side.

• **Note** If an angle does not appear acute in the first quadrant, you can work in any of the four quadrants to make the angle acute!!

• Find the values of all six trig functions and the angle of measure of angle Ɵ, where P(-3, 2) is a point on the terminal side of Ɵ.

• Find all the values of all six trig functions for the quadrantal angles of:

30, , , , 22 2