Mathematics 9709/33 May/June 2021: question paper and mark scheme
Cambridge AS & A Level Mathematics (9709), Paper 3 Pure Mathematics 3, May/June 2021. Read both free below, or download them. Done the paper? Get it marked by AI against this mark scheme.
1 State correct first two terms 1 + 2x B1
State a correct unsimplified version of the x 2 or x3 term M1 Symbolic binomial coefficients are not sufficient for the M
mark.
Obtain the next term −x 2 A1
4 3 A1
Obtain the final term x
3
4
Solve the equation 4x = 3 + 4−x . Give your answer correct to 3 decimal places. [5]
Mark scheme
2 State or imply u 2 − 3u − 1 = 0 , or equivalent in 4 x B1
Solve for u or 4 x M1
1 A1
Obtain root
2
( )
3 + 13 , or decimal in [3.30, 3.31]
Use correct method for finding x from a positive root M1
Obtain answer x = 0.862 and no other A1
5
The parametric equations of a curve are
x = t + ln t + 2, y = t − 1e−2t , where t > −2.
dy
(a) Express in terms of t, simplifying your answer. [5]
dx
(b) Find the exact y-coordinate of the stationary point of the curve. [2]
15 − 6x
Let f x =
1 + 2x 4 − x
Mark scheme
3(a) dx 1 B1
State =1+
dt t+2
Use product rule M1
dy A1 OE
Obtain = e −2t − 2 ( t − 1) e −2t
dt
dy dy dx M1
Use = ÷
dx dt dt
Obtain correct answer in any simplified form, A1
( 3 − 2t )( t + 2 ) −2t
e.g. e
t +3
5
3(b) Equate derivative to zero and solve for t M1
3 1 A1
Obtain t = and obtain answer y = e −3 , or exact equivalent
2 2
2
.
(a) Express f x in partial fractions. [3]
0a1
(b) Hence find Ó f x dx, giving your answer in the form ln
2
, where a and b are integers. [4]
1 b
Mark scheme
4(a) A B M1
State or imply the form + and use a correct method to
1 + 2x 4− x
find a constant
Obtain one of A = 4 and B = – 1 A1
Obtain the second value A1
3
4(b) Integrate and obtain terms 2ln (1 + 2 x ) + ln ( 4 − x ) B1FT The FT is on A and B.
+B1FT
Substitute limits correctly in an integral of the form M1
a ln (1 + 2 x ) + b ln ( 4 − x ) , where ab ≠ 0
50 A1
Obtain final answer ln
27
4
(a) By first expanding tan 21 + 21, show that the equation tan 41 = 12 tan 1 may be expressed as tan4 1 + 2 tan2 1 − 7 = 0. [4]
(b) Hence solve the equation tan 41 = 12 tan 1, for 0Å < 1 < 180Å. [3]
Mark scheme
5(a) Use double angle formula to express tan 4θ in terms of tan 2θ M1
Use double angle formula to express result in terms of tan θ M1
Obtain a correct equation in tan θ in any form A1
Obtain the given answer A1
4
5(b) Solve for tan θ and obtain a value of θ M1
Obtain answer, e.g. 53.5° A1
Obtain second answer, e.g. 126.5° and no other in the interval A1 Ignore answers outside the given interval. Treat answers in
radians as a misread.
3
(a) By sketching a suitable pair of graphs, show that the equation cot 21 x = 1 + e−x has exactly one root in the interval 0 < x ≤ π. [2]
(b) Verify by calculation that this root lies between 1 and 1.5. [2]
A @
(c) Use the iterative formula xn+1 = 2 tan−1
1
1 + e−xn to determine the root correct to 2 decimal places. Give the result of each iteration to 4 decimal places. [3]
Mark scheme
6(a) 1 B1
Sketch a relevant graph, e.g. y = cot x
2
Sketch a second relevant graph, e.g. y = 1 + e− x , and justify the B1
given statement
2
6(b) Calculate values of a relevant expression or pair of expressions at M1
x = 1 and x = 1.5
Complete the argument correctly with correct calculated values A1
2
6(c) Use the iterative formula correctly at least once M1
Obtain final answer 1.34 A1
Show sufficient iterations to 4 d.p. to justify 1.34 to 2 d.p. or show A1
there is a sign change in the interval (1.335, 1.345)
3
y
P
x
O M N
For the curve shown in the diagram, the normal to the curve at the point P with coordinates x, y meets the x-axis at N . The point M is the foot of the perpendicular from P to the x-axis.
The curve is such that for all values of x in the interval 0 ≤ x < 12 π, the area of triangle PMN is equal to tan x.
=
MN dy
(a) (i) Show that . [1]
y dx
= tan x. dy
(ii) Hence show that x and y satisfy the differential equation 12 y2 [2]
dx
(b) Given that y = 1 when x = 0, solve this differential equation to find the equation of the curve, expressing y in terms of x. [6]
Mark scheme
7(a)(i) MN dy B1
Justify the given statement =
y dx
1
7(a)(ii) dy M1
Express the area of PMN in terms of y and and equate to tan x
dx
Obtain the given equation correctly A1
2
7(b) Separate variables and integrate at least one side M1
1 3 A1
Obtain term y
6
Obtain term of the form ± ln cos x M1
Evaluate a constant or use x = 0 and y = 1 in a solution containing M1
terms ay 3 and ± ln cos x , or equivalent
1 3 1 A1
Obtain correct answer in any form, e.g. y = − ln cos x +
6 6
Obtain final answer y = 3 (1 − 6ln cosx) A1 OE
6
y
M
x
O
The diagram shows the curve y = ln x and its maximum point M . x4
(a) Find the exact coordinates of M . [4]
a
(b) By using integration by parts, show that for all a > 1, Ô dx < 19 . ln x
4
[6]
1 x
Mark scheme
8(a) Use quotient or product rule M1
Obtain correct derivative in any form A1
Equate derivative to zero and solve for x M1
1 A1
Obtain x = 4 e and y = , or exact equivalents
4e
4
8(b) 1 *M1
Commence integration and reach ax −3 ln x + b x −3 . dx
x
1 1 1 A1 OE
Obtain − x −3 ln x + x −3 . dx
3 3 x
1 1 A1
Complete integration and obtain − x −3 ln x − x −3
3 9
Substitute limits correctly, having integrated twice DM1
1 1 −3 1 A1 OE
Obtain answer − a ln a − a −3
9 3 9
Justify the given statement A1
6
ρ
The quadrilateral ABCD is a trapezium in which AB and DC are parallel. With respect to the origin O, the position vectors of A, B and C are given by OA = −i + 2j + 3k, OB = i + 3j + k and
−−¿
OC = 2i + 2j − 3k.
(a) Given that DC = 3AB, find the position vector of D. [3]
(b) State a vector equation for the line through A and B. [1]
(c) Find the distance between the parallel sides and hence find the area of the trapezium. [5]
(a) Verify that −1 + 2i is a root of the equation z4 + 3z2 + 2z + 12 = 0.
Mark scheme
9(a) State or imply AB = 2i + j − 2k B1 OE
ρ
Carry out a correct method to find OD M1
Obtain answer −4i − j + 3k A1 OE
3
ρ
9(b) State r = −i + 2 j + 3k + λ ( 2i + j − 2k ) B1FT OE. The FT is on AB .
1
ρ ρ
9(c) For a general point P on AB, state CP or DP in component form, *M1
ρ
e.g. CP = ( 3 − 2λ , −λ , −6 + 2λ )
Equate a relevant scalar product to zero or equate derivative of DM1
ρ
CP to zero or use Pythagoras in a relevant triangle and solve for λ
Obtain λ = 2 A1
Show the perpendicular is of length 3 A1
Carry out a correct method to find the area of ABCD and obtain the A1
answer 18
Alternative method for Question 9(c)
Use a scalar product to find the projection CN (or DN) of BC *M1
(or AD) on CD
Obtain CN = 3 (or DN = 3) A1
Use Pythagoras to obtain BN (or AN) DM1
9(c) cont’d Obtain answer 3 A1
Carry out a correct method to find the area of ABCD and obtain the A1
answer 18
5
[3]
(b) Find the other roots of this equation. [7]
Additional Page
If you use the following lined page to complete the answer(s) to any question(s), the question number(s) must be clearly shown.
Mark scheme
10(a) Substitute −1 + 2i and attempt expansions of the z 2 and z 4 terms M1
Use i 2 = −1 at least once M1
Complete the verification correctly A1
3
10(b) State second root −1 − 2i A1
Carry out a method to find a quadratic factor with zeros −1 ± 2i M1
Obtain z 2 + 2 z + 3 A1
Commence division and reach partial quotient z 2 + kz M1
Obtain second quadratic factor z 2 − 2 z + 4 A1
Solve a 3-term quadratic and use i 2 = −1 M1
Obtain roots 1 + 3i and 1 − 3i A1
7
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On this page, free: the mark scheme for AS & A Level Mathematics 9709/33, May/June 2021 (9709_s21_ms_33), and the question paper (9709_s21_qp_33), to read or download, with each question's marking points written out underneath.
How many marks is 9709/33 out of?+
Mathematics 9709/33 for May/June 2021 is out of 75 marks, with 1 hour 50 minutes to answer it.
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