w w ap eP m e tr .X w CAMBRIDGE INTERNATIONAL EXAMINATIONS s er Cambridge Ordinary Level om .c MARK SCHEME for the October/November 2014 series 4037 ADDITIONAL MATHEMATICS 4037/22 Paper 2, maximum raw mark 80 This mark scheme is published as an aid to teachers and candidates, to indicate the requirements of the examination. It shows the basis on which Examiners were instructed to award marks. It does not indicate the details of the discussions that took place at an Examiners’ meeting before marking began, which would have considered the acceptability of alternative answers. Mark schemes should be read in conjunction with the question paper and the Principal Examiner Report for Teachers. Cambridge will not enter into discussions about these mark schemes. Cambridge is publishing the mark schemes for the October/November 2014 series for most Cambridge IGCSE®, Cambridge International A and AS Level components and some Cambridge O Level components. ® IGCSE is the registered trademark of Cambridge International Examinations. Page 2 1 Mark Scheme Cambridge O Level – October/November 2014 Syllabus 4037 Paper 22 (a) B1 B1 (b) No.in H only = 50 − x ; No in F only = 60 − x Sum: 50 − x + 60 − x + x + 30 − 2 x = 98 A1 x = 14 2 3 B1 M1 9 x 2 + 2 x − 1 < ( x + 1) 2 M1 8 x 2 < 2 oe isw 1 1 − <x< 2 2 A1 log 2 ( x + 3) = log 2 y + 2 → x + 3 = 4 y B1 Expand and collect terms A1 log 2 ( x + y ) = 3 → x + y = 8 x + 3 = 4(8 − x ) B1 M1 5 x = 29 → x = 5.8, oe y = 2.2 oe Both written or on diagram Add at least 3 terms each with x involved and equate to 98 soi Eliminate y or x from two linear three term equations A1 A1 © Cambridge International Examinations 2014 Page 3 4 (i) Mark Scheme Cambridge O Level – October/November 2014 f ( 37 ) = 3 or gf ( x ) = gf ( 37 ) = (ii) y= ( x + 3) (iii) ( ) x −1 − 3 − 3 3−2 1 = 6−3 3 +1= f −1 ( y + 3) ( x) 2 = x −1 oe isw B1 x−2 2x − 3 2 xy − 3 y = x − 2 → 2 xy − x = 3 y − 2 M1 Rearrange and square in any order A1 Interchange x and y and complete M1 Multiply and collect like terms A1 Interchange and complete Mark final answer y= 3x − 2 = g −1 ( x ) oe 2x −1 5 (i) B = 900 B1 (ii) B = 500 + 400e2 = 3455 or 3456 or 3460 B1 (iii) dB = 80e 0.2t dt dB t = 10 → = 80e 2 = 591 ( /day ) dt (iv) 10000 = 500 + 400e0.2t 0.2t = ln 23.75 t = 15.8 ( days ) Paper 22 B1 x −1 − 3 → 2 2 x −1 − 3 − 2 Syllabus 4037 → e0.2t = ( 23.75) 3455.6 scores B0 B1 B1 awrt M1 DM1 e0.2t = k take logs: 0.2t = ln k A1 awrt © Cambridge International Examinations 2014 Page 4 6 (i) Mark Scheme Cambridge O Level – October/November 2014 (x + 2)2 + x 2 = 10 M1 A1 A1 or elimination of x leads to y2 – 2y – 3 = 0, then as above m 2 x 2 + 10mx + 25 + x 2 = 10 (m 2 ) + 1 x 2 + 10mx + 15 = 0 b − 4ac = ( 0 ) → 100m 2 − 60 ( m 2 + 1) = 0 B1 attempt to use discriminant on three term quadratic. Allow unsimplified A1 cao ± is required B1 allow unsimplified Attempt to solve with x 2 + y 2 = 10 M1 Eliminate x or y y = 2, x = ± 6 3 oe m=± 6 A1 both (i) v = 2cost + 1 B1 mark final answer (ii) 2cost + 1 = 0 M1 A1 equate their v to zero (must be a differential) and attempt to solve to find an angle awrt B1 awrt B1ft ft their v (2nd differential) DB1ft ft using their angle t in correct a awrt 2 2 dy ( 2 + x ) × 2 x − x × 2 x 4x = = 2 2 dx ( 2 + x2 ) ( 2 + x2 ) M1 A1 apply quotient or product rule unsimplified k =4 A1 k=4 does not need to be specifically identified 1 × original function their k m=± 3 oe isw 2 Alternative solution: dy x dy −x =− or = 2 dx y dx 10 − x Result: y 2 = x 2 + 5 y after inserted in y = mx + 5 t= (iii) 8 3 term quadratic with attempt to solve both x or a pair both y or second pair M1 A1 2 7 Paper 22 B1 x 2 + 2 x − 3 = 0 → ( x + 3)( x − 1) = 0 Points (1, 3), (–3, –1) isw (ii) Syllabus 4037 (i) (ii) A1 2π or 2.09 3 2π 2π 2π → x = 2sin = 3.83m + 3 3 3 a = −2 sin t 2π 1.73 −2 t= a=− 3=− ms 3 4 t= x2 1 d x = × + ( c ) isw ∫ 2 + x2 2 4 2 + x2 ( ) x B1 B1 © Cambridge International Examinations 2014 Page 5 (a + 3 5 ) 9 10 Mark Scheme Cambridge O Level – October/November 2014 2 (i) = a 2 + 3 5a + 3 5a + 45 oe (i) anywhere B1 B1 ( a + 3)( a − 2 ) = 0 M1 a = –3, 2 b = –18, 12 A1 A1 Attempt to solve three term quadratic with integer coefficients obtained by equating coeffs Both as correct or one correct pair Both bs correct B1 anywhere B1 anywhere B1ft correct addition of their terms B1 use of identity and cancel 3cot x − cot x = tan x → 2cot x = tan x M1 tan 2 x = 2 oe x = 54.7, 125.3, 234.7, 305.3 A1 A1 A1 equate and collect like terms, allow sign errors secxcosecx = 1 cos xsin x cos x sin x 1 − cos 2 x LHS = oe cos x sin x sin 2 x = = tan x cos x sin x 11 AG 1 2 × x × 0.8 ( = 0.4 x 2 cm 2 ) 2 SR = 5sin 0.8 ( = 3.59 ) or 2 values only 2 more values. awrt B1 anywhere B1 SR may be seen in stated Area of triangle = 1 5cos 0.8 × 5sin 0.8 = 6.247 cm 2 2 0.08 x 2 = 6.247 M1 A1 insert correct terms into correct area formulae x = 8.837 cm A1 Area of sector = OR = 5cos0.8 ( = 3.48) (ii) AG 1 absin C 2 SQ = 8.84 − 5 ( = 3.84cm ) PR = 8.84 − 5cos0.8 ( = 5.35 or 5.36cm ) PQ = 8.84 × 0.8 ( = 7.07cm ) Perimeter = 19.84 to 19.86 cm or rounded to 19.8 or 19.9 (iii) Paper 22 Equate: a 2 + a + 45 = 51 and 6a − b = 0 cot x = (ii) B1 Syllabus 4037 Area PQSR = 4 × 6.247 = 25cm 2 B1 two lengths from SQ, PR, PQ awrt B1 B1 third length awrt sum M1 A1 24.95 to 25 © Cambridge International Examinations 2014 Page 6 12 (i) Mark Scheme Cambridge O Level – October/November 2014 f ( 2 ) = 3 ( 23 ) − 14 ( 22 ) + 32 = 0 Syllabus 4037 B1 Or complete long division f ( x ) = ( x − 2 ) ( 3 x 2 − 8 x − 16 ) f ( x ) = ( x − 2 )( x − 4 )( 3x + 4 ) M1 A1 M1 A1 (iii) x = 2, 4 B1 (iv) ∫ 3x − 14 + x (ii) 32 2 dx = 1.5 x 2 − 14 x − 4 32 Area = 1.5 x 2 − 14 x − x 2 = (–) 2 32 (+ c) x 3x2 and 16 8x and correct signs Factorise three term quadratic B1 B1 first 2 terms third term correct unsimplified M1 Limits of 2 and 4 and subtract A1 © Cambridge International Examinations 2014 Paper 22