vce mathematical methods (cas) units 3 & 4 - … · vce mathematical methods (cas) units 3...
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Trial Examination 2010
VCE Mathematical Methods (CAS) Units 3 & 4
Written Examination 1
Suggested Solutions
VCE Mathematical Methods (CAS) Units 3 & 4 Trial Examination 1 Suggested Solutions
Copyright © 2010 Neap TEVMMU34EX1_SS_2010.FM 2
Question 1
a. y-intercept (x = 0)
A1
b. x-intercepts (y = 0)
M1
OR M1
A1
Question 2
a. ,
thus A1
(Alternatively, using the product rule directly gives , which is
equivalent to the answer above.)
f 0( ) sin2 π2---–
1–=
1–( )2 1– =
0 =
sin2 2x π2---–
1– 0=
sin2 2x π2---–
1=
2x π2---–
sin 1±=
x 0 2π,[ ]∈2x 0 4π,[ ]∈∴
2xπ2--- π
2---–
7π2
-------,∈–∴
2x π2---–
sin 1–=
2x π2---–
π2--- 3π
2------- 7π
2-------, ,–=
2x 0 2π 4π,,=
x 0 π 2π, ,=
2x π2---–
sin 1=
2x π2---–
π2--- 5π
2-------,=
2x π 3π,=
xπ2--- 3π
2-------,=
x 0π2--- π
3π2
------- 2π, , , ,=
y x2loge 1x---
x2loge x 1–( ) x2loge x( )–= = =
dydx------ 2x– loge x( ) x2 1
x---⋅–⋅ 2xloge x( ) x––= =
dydx------ 2xloge
1x---
x2 1–x
------ +=
VCE Mathematical Methods (CAS) Units 3 & 4 Trial Examination 1 Suggested Solutions
Copyright © 2010 Neap TEVMMU34EX1_SS_2010.FM 3
b. For stationary points we require .
gives x = 0, M1
Clearly so a stationary point exists if .
Now
Thus the stationary point occurs at . A1
Sign of the derivative test: Use suitable values such as for , choose and for
, choose .
, M1
,
∴ a maximum turning point occurs at . A1
Question 3
a. f is a parabola with turning point (2, 4).
∴ maximum value of a is 2, so f is one-to-one. A1
b. inverse M1
A1
dydx------ 0=
x 1 2loge x( )+( )– 0= loge x( ) 12---–=
x 0> loge x( ) 12---– x⇒ e
12---–
= =
y e
12---–
2
loge× 1
e
12---–
-------
=
e 1– 12---× =
12e------ =
e
12---– 1
2e------,
x e
12---–
< x e 1–=
x e
12---–
> x 1=
x e 1–= dydx------ e 1– 1 2logee 1–+[ ]×– e 1– 1 2–( )× 0>–= =
x 1= dydx------ 1 1 2loge1+[ ]×– 1 1 0<×–= =
e
12---– 1
2e------,
x y 2–( )2 4+=
x 4– y 2–( )2=
y 2– x 4–±=
y 2 x 4– (as y ∞ 2 ) i.e. domain of f ),–(∈–=
f 1– x( )∴ 2 x 4––=
VCE Mathematical Methods (CAS) Units 3 & 4 Trial Examination 1 Suggested Solutions
Copyright © 2010 Neap TEVMMU34EX1_SS_2010.FM 4
c. rule of
domain of
∴ graph is: A1
Question 4
a.
correct identification of f and g A1
coordinates of P A1
b. Given , then . M1
Thus . A1
f 1– f x( )( ) x=
f 1– f x( )( ) domain f ∞ 2 ),–(= =
y
x0
2
2
(2, 2)
y
xO
1.0
2.0
P
π2---π
4---
f x( ) xtan=
g x( ) 2 xcos=
π4--- 1,
y loge x( )cos( )= dydx------ x( )sin–
x( )cos------------------ x( )tan–= =
x( )tan xd∫ log– e x( )cos( )=
VCE Mathematical Methods (CAS) Units 3 & 4 Trial Examination 1 Suggested Solutions
Copyright © 2010 Neap TEVMMU34EX1_SS_2010.FM 5
c. Area A1
M1
(or equivalent: or ) A1
Question 5
As events A and B are independent, . A1
Also, events will be independent so we know .
From the question, .
Thus , giving M1
A1
Question 6
Multiplying by gives: M1
A1
2 x( )cos x( )tan–( ) xd0
π4---
∫ =
2 x( )sin loge x( )cos( )+[ ]0
π4---
=
2π4---
sin logeπ4---
cos + 2 0sin loge 0cos+[ ]– =
2 1
2------- loge
1
2-------
+× 2 0× loge 1( )+[ ]– =
1 loge 2( )–= 1 loge1
2-------
+ 1 12---– loge 2( )
Pr A B( ) Pr A( ) 34--- Pr A ′( )⇒ 1
4---= = =
A ′ and B ′ Pr A ′ B ′∩( ) Pr A ′( ) Pr× B ′( )=
Pr B( ) Pr A ′ B ′∩( )=
Pr B( ) 14--- 1 Pr B( )–( )= 4 Pr B( ) 1 Pr B( )–( ) 5 Pr B( )⇒ 1= =
Pr B( ) 15---=
ex 4– 5e x–=
ex
ex( )2
4ex– 5=
ex( )2
4ex– 5– 0=
ex 5–( ) ex 1+( ) 0=
ex 5 or –1, ex 1–≠=
x loge5=
VCE Mathematical Methods (CAS) Units 3 & 4 Trial Examination 1 Suggested Solutions
Copyright © 2010 Neap TEVMMU34EX1_SS_2010.FM 6
Question 7
We require A1
M1
A1
Question 8
M1
Equation of tangent
A1
Hence to pass through (0, 0):
A1
Question 9
a.
∴ image is (0, –1). A1
Pr T 6 T 3≥≤( ) Pr 3 T 6≤ ≤( )Pr T 3≥( )
--------------------------------=
t–50------ 1
5---+ td
3
6
∫1 Pr T 3<( )–-------------------------------- =
t2–100--------- t
5---+
3
6
1 51100---------–
--------------------------
36–100--------- 6
5---+
9–100--------- 3
5---+
–
49100---------
------------------------------------------------------= =
27–100--------- 3
5---+
49100---------
------------------- = 33
100--------- 100
49---------× 33
49------= =
f a( ) a2 k+=
f ′ x( ) 2x=
f ′ a( ) 2a=
y a2 k+( )– 2a x a–( )=
y 2ax a2– k+=
a2– k+ 0=
k a2=
k 0≥∴
X ′ TX B+=
x'
y'
2 0
0 1–
2
3
4–
2+=
4
3–
4–
2+ =
0
1– =
VCE Mathematical Methods (CAS) Units 3 & 4 Trial Examination 1 Suggested Solutions
Copyright © 2010 Neap TEVMMU34EX1_SS_2010.FM 7
b.
M1
M1
becomes
A1
∴ required image is .
Alternatively, a more elegant solution which avoids the need to find an inverse matrix is shown below:
M1
⇒ Μ1
Adding gives .
∴ required image is . A1
c. A dilation of factor 2 from the y-axis and a reflection in the y-axis A1
followed by translations of 4 units to the left and 2 upwards. A1
Note: the order of the first two transformations could be exchanged and similarly, the order of the translations is not significant, however the translations must follow the dilation and reflection.
x ′y ′
2 0
0 1–
x
y
4–
2+=
x ′y ′
4–
2– 2 0
0 1–
x
y=
12–
------ 1– 0
0 2
x ′ 4+
y ′ 2–
12–
------ 1– 0
0 2
2 0
0 1–
x
y=
1 0
0 1
x
y=
x
y
12–
------ 1– 0
0 2
x ′ 4+
y ′ 2–=∴
x∴ x ′ 4+2
-------------=
y y ′– 2+=
y∴ 2x 4–= y ′– 2+ 2x ′ 4+
2-------------
4–=
y ′ 2 x ′–=
y 2 x–=
TX B+ 2 0
0 1–
x
2x 4+
4–
2+=
2x
2x– 4+
4–
2+=
X ′∴ 2x 4–
2x– 6+=
x ′ 2x 4–=
y ′ 2x– 6+=
x ′ y ′+ 2=
x y+ 2=
VCE Mathematical Methods (CAS) Units 3 & 4 Trial Examination 1 Suggested Solutions
Copyright © 2010 Neap TEVMMU34EX1_SS_2010.FM 8
Question 10
a. Approximate change M1
A1
b. The gradient function at is positive and increasing. Therefore the approximation of the change is less than the exact change. A1
V x h+( ) V x( )– =
hV ′ x( ) =
V 6x3, so V ′ x( ) 18x2==
x 3, h 0.02: hV ′ x( ) 0.02V ′ 3( )= = =
0.02 18 32××=
3.24=
3.24 cm3 =
x 3=