FOR OCR GCE Examinations Advanced / Advanced Subsidiary Core Mathematics C4 Paper B MARKING GUIDE This guide is intended to be as helpful as possible to teachers by providing concise solutions and indicating how marks could be awarded. There are obviously alternative methods that would also gain full marks. Method marks (M) are awarded for using a valid method. Accuracy marks (A) can only be awarded when a correct method has been used. (B) marks are independent of method marks. Written by Shaun Armstrong Solomon Press These sheets may be copied for use solely by the purchaser’s institute. C4 Paper B – Marking Guide 1. u = x, u′ = 1, v′ = e3x, v = 1 3 e3x M1 A1 ∫ I = = 1 1 3x x e3x − e dx 3 3 3x 1 1 3x xe − 9e +c 3 2. M1 A1 x2 + 0 x + 1 x4 + x3 − 5 x2 + 0 x x4 + x3 − 6 x2 x2 + 0 x x2 + x − x 2 x +x−6 − 9 M2 − 9 − 6 − 3 ∴ quotient = x2 + 1, remainder = −x − 3 3. 4. A2 (i) = −cosec2 x2 × 2x = −2x cosec2 x2 M1 A1 (ii) = cos x × (3 + 2 cos x) − sin2x × (−2sin x) M1 A1 2 2 = 3cos x + 2 cos x +22sin x = 3cos x + 2 2 M1 A1 (3 + 2 cos x) (3 + 2 cos x ) (i) (3 + 2 cos x) (1 − 3x)−2 = 1 + (−2)(−3x) + ( −2)( −3) 2 2 3 (−3x)2 + ( −2)( −3)( −4) 3× 2 (−3x)3 + … = 1 + 6x + 27x + 108x + … (ii) 2− x 1 − 3x 2 ∴ for small x, (i) (ii) 6. (i) (ii) 2− x 1 − 3x 2 = 4 + 20x + 85x2 + 330x3 dx dy −1 = 12 at 2 , = a(1 − 2t) dt dt dy a(1 − 2t ) = = 2 t (1 − 2t) 1 1 at − 2 dx 2 A3 A1 A1 M1 A1 4s = −7 − 3t (1) 7 − 3s = 1 (2) −4 + s = 8 + 2t (3) (2) ⇒ s = 2, sub. (1) ⇒ t = −5 check (3) −4 + 2 = 8 − 10, true ∴ intersect intersect at (7j − 4k) + 2(4i − 3j + k) = (8i + j − 2k) M1 B1 M1 A1 A1 4 × (−3) + (−3) × 0 + 1× 2 = 57.0° (1dp) M1 A1 Solomon Press C4B MARKS page 2 (8) M1 A1 16 + 9 + 1 × 9 + 0 + 4 −10 26 × 13 (7) M1 B1 M1 A1 M1 A1 = cos−1 (6) M1 y = 0 ⇒ t = 0 (at O) or 1 (at A) t = 1, x = a, y = 0, grad = −2 ∴ y − 0 = −2(x − a) at B, x = 0 ∴ y = 2a area = 12 × a × 2a = a2 = cos−1 (4) = (2 − x)2(1 − 3x)−2 = (4 − 4x + x2)(1 + 6x + 27x2 + 108x3 + …) M1 = 4 + 24x + 108x2 + 432x3 − 4x − 24x2 − 108x3 + x2 + 6x3 + … 5. (4) (9) 7. (i) ∫ ∫ dy = −ke−0.2t dt M1 −0.2t y = 5 ke +c t = 0, y = 2 ⇒ 2 = 5k + c, ∴ y = 5ke−0.2t − 5k + 2 (ii) t = 2, y = 1.6 ⇒ 1.6 = 5ke−0.4 − 5k + 2 k= (iii) 8. (i) A1 M1 A1 c = 2 − 5k −0.4 = 0.2427 (4sf) 5e −0.4 − 5 M1 A1 as t → ∞, y → h (in metres) ∴ “h” = −5k + 2 = 0.787 m = 78.7 cm ∴ h = 79 (2sf) dy dy + 4y =0 dx dx 2x − 4y − 4x grad = M1 A1 3 2 M1 ∴ y−2= 3 2 (x − 1) M1 2y − 4 = 3x − 3 3x − 2y + 1 = 0 (iii) x − 2y 2x − 2 y A1 3 2 = M1 2(x − 2y) = 3(2x − 2y), y = 2x sub. ⇒ x2 − 8x2 + 8x2 = 1 x2 = 1, x = 1 (at P) or −1 ∴ Q (−1, −2) 9. (i) (ii) A1 M1 A1 du = cos x dx u = sin x ⇒ 6cos x I = ∫ cos 2 x (2 − sin x) = ∫ (1 − u 2 )(2 − u ) 6 6 (1 + u )(1 − u )(2 − u ) ≡ dx = 6cos x ∫ (1 − sin 2 x)(2 − sin x) dx du A 1+ u (iii) 6 ≡ (1 − u 2 )(2 − u ) 1 1+ u x = 0 ⇒ u = 0, x = I = 1 2 ∫0 ( 1 1+ u + 3 1− u π 6 − B 1− u + C 2−u + + 3 1− u ⇒ u= 2 2−u = (ln − 3 ln M1 A1 A1 A1 2 2−u − 1 2 M1 ) du 1 1 2 M1 M1 A1 = [ln1 + u − 3 ln1 − u + 2 ln2 − u] 02 3 2 (11) B1 6 ≡ A(1 − u)(2 − u) + B(1 + u)(2 − u) + C(1 + u)(1 − u) u = −1 ⇒ 6 = 6A ⇒ A=1 u=1 ⇒ 6 = 2B ⇒ B=3 u=2 ⇒ 6 = −3C ⇒ C = −2 ∴ (9) M1 A1 dy 2x − 4 y x − 2y = = 4x − 4 y 2x − 2 y dx (ii) M1 M1 A1 3 2 + 2 ln ) − (0 + 0 + 2 ln 2) M1 A1 M1 = 3 ln 32 + 3 ln 2 − 2 ln 2 = 3 ln 3 − 3 ln 2 + ln 2 = 3 ln 3 − 2 ln 2 M1 A1 (14) Total (72) Solomon Press C4B MARKS page 3 Performance Record – C4 Paper B Question no. Topic(s) 1 2 3 4 5 6 7 8 9 Total integration algebraic differentiation binomial parametric vectors differential differentiation integration, division series equations equation partial fractions Marks 4 4 6 7 8 Student Solomon Press C4B MARKS page 4 9 9 11 14 72
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