FOR OCR GCE Examinations Advanced / Advanced Subsidiary Core Mathematics C2 Paper C 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. C2 Paper C – Marking Guide 1. tan2 θ = 1 3 1 3 tan θ = ± θ = 2. π 6 π 6 , M1 A1 π 6 − π or π − π 6 π 6 , − π6 B1 M1 θ = − 5π 6 (i) = log2 (32 × 5) = 2 log2 3 + log2 5 = 2p + q (ii) = log2 , − , 5π 6 , 3 5× 2 A1 B1 M1 A1 = log2 3 − log2 5 − log2 2 =p−q−1 3. (i) =1+ (ii) 4. (i) (ii) 1 4 1 4 nx + 1 32 n(n − 1) 2 1 32 (i) ( 14 x)2 + ... A1 n(n − 1) M1 8n = n(n − 1) n[8 − (n − 1)] = 0 n≠0 ∴n=9 M1 A1 n= 7 − 2x − 3x2 = M1 A1 x = −2 is a solution ∴ (x + 2) is a factor B1 + 1 − 7x + 2 − 7x − 8x x + 2 x + 2 M1 A1 ∴ ( 13 , 6), (1, 2) A1 (− 4 x3 f(x) = 2x + c (−1, 3) ∴ 3 = 2 + c c=1 −2 f(x) = 2x + 1 = 4 ∫1 M1 A1 M1 A1 (2x−2 + 1) dx = [−2x−1 + x] 14 = ( − 12 C2C MARKS page 2 (8) ) dx −2 (ii) M1 A1 ∴ (x + 2)(3x2 − 4x + 1) = 0 (x + 2)(3x − 1)(x − 1) = 0 x = −2 (at P), 13 , 1 ∫ (6) 2 x 7x − 2x2 − 3x3 = 2 3x3 + 2x2 − 7x + 2 = 0 f(x) = (6) B1 M1 n(n − 1)x2 + ... 3x2 − 4x x + 2 3x3 + 2x2 3x3 + 6x2 2 − 4x 2 − 4x 5. M1 B1 A1 = 1 + n( 14 x) + (5) + 4) − (−2 + 1) = M1 A1 4 12 M1 A1 Solomon Press (8) 6. (i) sin A 8 sin1.7 14 = 4 7 sin A = (ii) 7. (a) (b) M1 sin 1.7 ∠BAC = 0.6025 ∠ACB = π − (1.7 + 0.6025) = 0.839 (3sf) A1 M1 A1 AB2 = 82 + 142 − (2 × 8 × 14 × cos 0.8391) AB = 10.50 P = 10.50 + (14 − 8) + (8 × 0.8391) = 23.2 cm (3sf) M1 A1 M1 A1 = 31 × 3x = 3y = 3−1 × (3x)2 = (i) (ii) 1 3 3y − 1 3 M1 A1 M1 A1 y2 y2 = 6 y2 − 9y + 18 = 0 (y − 3)(y − 6) = 0 y = 3, 6 3x = 3, 6 M1 A1 lg 6 lg 3 x = 1, B1 M1 x = 1, 1.63 (3sf) 8. (i) 3 ∫1 A1 (x2 − 2x + k) dx = [ 13 x3 − x2 + kx] 13 = (9 − 9 + 3k) − ( 13 − 1 + k) = 2k + 2 3 ∴ 2k + = lim [ −4x − 32 k →∞ ] k2 M2 A1 k →∞ M1 2 2 k2 = lim ( 2 − 4 )= 3 2 A1 r = 6 −48 = 3 a= −48 − 12 = (iii) Sn = M1 A1 = 96 96 1 − (− 12 ) (ii) B1 − 18 − 18 = − 12 r= A1 = 64 96[1 − (− 12 )n ] 1 − (− 12 ) (11) k2 ar = −48, ar4 = 6 3 M1 M1 A1 k →∞ (i) M1 A2 = 8 23 4 4 = lim {− 3 − (− )} 9. (9) 2 3 k=4 (ii) (8) M1 A1 = 64[1 − ( − 12 )n] S∞ − Sn = 64 − 64[1 − ( − 12 )n] M1 = 64( − 12 )n = 26 × (−1)n × 2−n = (−1)n × 26 − n difference is magnitude, ∴ = 2 M1 A1 6−n Solomon Press M1 A1 (11) Total (72) C2C MARKS page 3 Performance Record – C2 Paper C Question no. 1 2 3 4 5 6 7 8 9 Topic(s) trig. eqn logs binomial factor theorem, alg. div. area by integr. sine rule, sector of a circle logs integr. GP Marks 5 6 6 8 8 8 9 11 11 Student C2C MARKS page 4 Solomon Press Total 72
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