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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.

9709_w19_qp_119709_w19_ms_119709/11/O/N/19

Paper
Paper 1
Total marks
75
Time
1 hour 45 minutes
Code on the paper
9709/11/O/N/19
9709_w19_ms_11.pdf

9709/11 mark scheme, question by question

Each question as it's printed, and the mark scheme's points for it, as text. Diagrams, tables and graphs are in the PDFs above.

Question 13 marks

Question

Find the term independent of x in the expansion of 2x + 2 . [3] 4x

Mark scheme

1 1 B1 SOI 6C2 × ( 2 x ) × 4 (4 x 2 ) 2 SC: Condone errors in (4−1 )2 evaluation or interpretation for B1 only 1 B1 Identified as required term. 15 × 24 × 42 15 B1 3

Question 23 marks

Question

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

Question 35 marks

Question

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

Question 45 marks

Question

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

Question 57 marks

Question

(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

Question 67 marks

Question

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

Question 78 marks

Question

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

Question 88 marks

Question

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

Question 910 marks

Question

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

Question 109 marks

Question

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]

Mark scheme

10(i)  2   −1   3   4   2   2 B1B1 Condone reversal of labels             AB =  −3  −  3  =  −6  , BC =  −2  −  −3  =  1   5   −4   9   5   5   0             AB.BC = 6 ‒ 6 → = 0 (hence perpendicular) B1 AG 10(ii)  4 2  2 B1  −2          DC =  −2  −  2  =  −4  Or: CD =  4   5   −1  6   −6          AB = kDC M1 OE 3 Expect k = 2 Or: DC.BC = 4 ‒ 4 = 0 hence BC is also perpendicular to DC Or: AB.DC = 1 or AB.CD = –1, angle between lines is 0 or 180 AB is parallel to DC, hence ABCD is a trapezium A1 10(iii) |AB| = 9 + 36 + 81 = 126 = 11.22 M1 Method for finding at least 2 magnitudes |DC| = 4 + 16 + 36 = 56 = 7.483 |BC| = 4 + 1 + 0 = 5 = 2.236 Area = 12 ( theirAB + theirDC ) × theirBC = 20.92 M1A1 OE

Question 1110 marks

Question

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.