Mathematics 9709/11 October/November 2019: question paper and mark scheme
Cambridge AS & A Level Mathematics (9709), Paper 1, October/November 2019. Read both free below, or download them. Done the paper? Get it marked by AI against this mark scheme.
An increasing function, f, is defined for x > n, where n is an integer. It is given that f ′ x = x2 − 6x + 8.
Find the least possible value of n. [3]
Mark scheme
2 Attempt to solve f ′ ( x ) = 0 or f ′ ( x ) > 0 or f ′ ( x ). 0 M1 SOI
(x – 2)(x – 4) A1 2 and 4 seen
(Least possible value of n is) 4 A1 Accept n = 4 or n . 4
3
The line y = ax + b is a tangent to the curve y = 2x3 − 5x2 − 3x + c at the point 2, 6. Find the values of the constants a, b and c. [5]
Mark scheme
3 dy B1
= 6 x 2 − 10 x − 3
dx
dy M1
At x = 2, = 24 − 20 − 3 = 1 → a = 1 A1
dx
6= 2+b → b = 4 B1FT Substitute x = 2, y = 6 in y = ( their a ) x + b
6 = 16 − 20 − 6 + c → c = 16 B1 Substitute x =2, y = 6 into equation of curve
5
A runner who is training for a long-distance race plans to run increasing distances each day for 21 days.
She will run x km on day 1, and on each subsequent day she will increase the distance by 10% of the previous day’s distance. On day 21 she will run 20 km.
(i) Find the distance she must run on day 1 in order to achieve this. Give your answer in km correct to 1 decimal place. [3]
(ii) Find the total distance she runs over the 21 days. [2]
1
Mark scheme
4(i) Identifies common ratio as 1.1 B1
Use of x (1.1) = 20 M1 SOI
20
A1 Accept 2.97
20
x= = 3.0
(1.1)20
3
4(ii) (1.1)21 − 1 M1 Correct formula used for M mark.
their 3.0 × → 192 A1 Allow 2.97 used from (i)
1.1 − 1 Accept 190 from x = 2.97…
2
(i) Given that 4 tan x + 3 cos x + = 0, show, without using a calculator, that sin x = − 23 . [3]
cos x
(ii) Hence, showing all necessary working, solve the equation
1
4 tan 2x − 20Å + 3 cos 2x − 20Å + =0 cos 2x − 20Å for 0Å ≤ x ≤ 180Å. [4]
Mark scheme
5(i) 1 M1 Multiply by cos x or common denominator of cos x
4 tan x + 3cos x + = 0 → 4sin x + 3cos 2 x + 1 = 0
cos x
( )
4sin x + 3 1 − sin 2 x + 1 = 0 → 3sin 2 x − 4sin x − 4 = 0 M1 Use cos2 x = 1 − sin 2 x and simplify to 3-term quadratic in
sin x
2 A1 AG
sin x = −
3
3
5(ii) 2x ‒20º = 221.8º, 318.2º M1A1 Attempt to solve sin ( 2 x − 20 ) = −2 / 3 ( M1) .
At least 1 correct (A1)
x = 120.9º, 169.1º A1 FT for 290º ‒ other solution.
A1FT SC A1 both answers in radians
4
A straight line has gradient m and passes through the point 0, −2. Find the two values of m for which the line is a tangent to the curve y = x2 − 2x + 7 and, for each value of m, find the coordinates of the point where the line touches the curve. [7]
Mark scheme
6 Equation of line is y = mx − 2 B1 OR
x 2 − 2 x + 7 = mx − 2 → x 2 − x ( 2 + m ) + 9 = 0 M1
Apply b 2 − 4ac ( = 0 ) → ( 2 + m ) − 4 × 9 ( = 0 ) *M1
2
m = 4 or −8 A1
2
m = 4→ x ‒ 6x + 9 = 0 → x = 3 DM1
m = ‒8→ x2 + 6x + 9 = 0 → x = ‒3
(3, 10), (‒3, 22) A1A1
Alternative method for question 6
dy B1
= 2x ‒ 2
dx
2x − 2 = m M1
x2 − 2 x + 7 = ( 2 x − 2) x − 2 = 2 x2 − 2 x − 2 M1
x 2 − 9 = 0 → x = ±3 A1
(3, 10), (‒3, 22) A1A1
When x = 3, m = 4; when x = ‒3, m = ‒8 A1
7
Functions f and g are defined by
3 f:x→ for x > 0,
2x + 1
1 g : x → + 2 for x > 0. x
(i) Find the range of f and the range of g. [3]
ax
(ii) Find an expression for fg x, giving your answer in the form , where a, b and c are integers. bx + c
[2]
(iii) Find an expression for fg−1 x, giving your answer in the same form as for part (ii). [3]
Mark scheme
7(i) Range of f is 0 < f(x) < 3 B1B1 OE. Range cannot be defined using x
Range of g is g(x) > 2 B1 OE
3
7(ii) B1B1 Second B mark implies first B mark
( fg ( x ) = ) 2 1 +32 + 1 = 2 +3x5 x
(x )
2
7(iii) 3x M1 Correct order of operations
y= → 2 y + 5 xy = 3 x → 3 x − 5 xy = 2 y
2 + 5x
2y M1 Correct order of operations
x (3 − 5 y ) = 2 y → x=
3 − 5y
(( fg ) ( x )) = 3 −2 x5x
−1 A1
3
C
B
6 cm
3
8 0 rad
O A
The diagram shows a sector OAC of a circle with centre O. Tangents AB and CB to the circle meet at B. The arc AC is of length 6 cm and angle AOC = 38 0 radians.
(i) Find the length of OA correct to 4 significant figures. [2]
(ii) Find the perimeter of the shaded region. [2]
(iii) Find the area of the shaded region. [4]
dy 1
Mark scheme
8(i) 3 M1
OA × π = 6
8
16 A1
OA = = 5.093 ( 0 )
π
8(ii) 3 M1
AB = their 5.0930 × tan π
16
Perimeter = 2 × 3.4030 + 6 = 12.8 A1
8(iii) Area OABC = ( 2 × ½ ) × their 5.0930 × their 3.4030 M1
3 M1
Area sector = ½ × ( their 5.0930 ) × π
2
8
Shaded area = their17.331 − their15.279 = 2.05 M1A1
A curve for which = 5x − 1 2 − 2 passes through the point 2, 3. dx
(i) Find the equation of the curve. [4]
d2 y
(ii) Find . [2]
dx2
(iii) Find the coordinates of the stationary point on the curve and, showing all necessary working, determine the nature of this stationary point. [4]
Mark scheme
9(i) y = [( 5 x − 1) ÷ 32 ÷5 ] [ − 2 x ] B1
1/ 2
B1
27 M1 Substitute x = 2, y = 3
3= −4+c
(3 / 2) × 5
3
A1
18 17 2 ( 5 x − 1) 2 17
c=7− = → y= − 2x +
5 5 15 5
9(ii) d 2 y / dx 2 = ½ ( 5 x − 1) [×5]
−1/2 B1
B1
9(iii) ( 5 x − 1)1/ 2 − 2 = 0 → 5 x − 1 = 4 M1A1 dy
Set = 0 and attempt solution (M1)
x =1 dx
16 17 37 A1 37
y= −2+ = Or 2.47 or 1,
25 5 15 15
d2 y 5 1 5 A1 OE
= × = (> 0) hence minimum
dx x 2 2 4
D C
A B
Relative to an origin O, the position vectors of the points A, B, C and D, shown in the diagram, are given by
` a ` a ` a ` a
OA = 3 , OB = −3 , OC = −2 and OD = 2 .
−4 5 5 −1
(i) Show that AB is perpendicular to BC. [3]
(ii) Show that ABCD is a trapezium. [3]
(iii) Find the area of ABCD, giving your answer correct to 2 decimal places. [3]
y
3
y = x2 + 4x + 3
x
−2 O y = −1
−1
The diagram shows a shaded region bounded by the y-axis, the line y = −1 and the part of the curve y = x2 + 4x + 3 for which x ≥ −2.
(i) Express y = x2 + 4x + 3 in the form y = x + a2 + b, where a and b are constants. Hence, for x ≥ −2, express x in terms of y. [4]
(ii) Hence, showing all necessary working, find the volume obtained when the shaded region is rotated through 360Å about the y-axis. [6]
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
11(i) ( y =) ( x + 2) − 1
2 B1 2nd B1 dependent on 2 in bracket
DB1
x + 2 = ( ± )( y + 1) M1
1/ 2
x = −2 + ( y + 1) A1
1/ 2
11(ii) x 2 = 4 + ( y + 1) − / + 4 ( y + 1) 2
1
*M1A1 SOI. Attempt to find x 2 .The last term can be ‒ or + at this
stage
3
A2,1,0
y 2 4 ( y + 1) 2
( π ) ∫ x ( dy ) = ( π ) 5 y + − 3
2
2
2
9 64 1 DM1 Apply y limits
( π ) 15 + − − −5 +
2 3 2
8π A1
or 8.38
3
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Where can I find the 9709/11 October/November 2019 mark scheme?+
On this page, free: the mark scheme for AS & A Level Mathematics 9709/11, October/November 2019 (9709_w19_ms_11), and the question paper (9709_w19_qp_11), to read or download, with each question's marking points written out underneath.
How many marks is 9709/11 out of?+
Mathematics 9709/11 for October/November 2019 is out of 75 marks, with 1 hour 45 minutes to answer it.
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Yes. Upload your answers to 9709/11/O/N/19 as a PDF or photos, and CIE Buddy marks every question against this paper's official mark scheme, using Cambridge's marking rules. You get your score, each lost mark explained on your own script, and the topics to revise. It's a guide, not an official Cambridge grade.