4754A Mark Scheme June 2014 BUT

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Hilary Bruce
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1 4754A Mark Scheme June 04 3x A Bx C ( x)(4 x ) x 4 x correct form of partial fractions ( condone additional coeffs eg A B BUT x 4 x ** is M0 ) Ax B Cx D x 4 x * for 3x = A(4 + x ) + (Bx + C)( x) Multiplying through oe and substituting values or equating coeffs at LEAST AS FAR AS FINDING A VALUE for one of their unknowns (even if incorrect) Can award in cases * and ** above Condone a sign error or single computational error for but not a conceptual error Eg 3x = A( x) + (Bx + C)(4 + x²) is M0 3x( x)(4 + x²) = A(4 + x²) + (Bx + C)( x) is M0 Do not condone missing brackets unless it is clear from subsequent work that they were implied. Eg 3x = A(4 + x²) + Bx + C( x) = 4A + Ax² + Bx + C Cx is M0 = 4A + Ax² + Bx Bx² + C Cx is x = 6 = 8A, A = ¾ oe www [SC A = 3/4 from cover up rule can be applied, then the applies to the other coefficients] A B NB A = 3/4 is A0 ww (wrong working) x 4 x x coeffs: 0 = A B B = ¾ oe www constants: 0 = 4A + C C = ½ oe www [In the case of * above, all 4 constants are needed for the final ] Ignore subsequent errors when recompiling the final solution provided that the coeffs were all correct [5]

2 4754A Mark Scheme June (4 x) 4 ( x ) 4 dealing with the 4 to obtain 3/ x 3/ 4 ( ) 4 3/ 3 / 3 / x 4 4 x 4... (or expanding as! and having all the powers of 4 correct) 3 3 4! 4 8( ( x).. ( x ) x +3/6 x² correct binomial coeffs for n = 3/ ie, 3/, 3/././! Not ncr form Indep of coeff of x Indep of first 8 + 3x www + 3/6 x² www Ignore subsequent terms Valid for 4 < x < 4 or x < 4 accept s or a combination of < and, but not 4 > x > 4, x > 4, or say 4 < x condone 4 < x < 4 Indep of all other marks [5] Allow MR throughout this question for n = m/ where m N, and m odd and then MR provided it is at least as difficult as the original.

3 4754A Mark Scheme June 04 3 (i) x y B,,0 For values ,0.679, (4dp or better soi) [accept truncated to 4 figs after dec point] A = ( /3) [( ) + ( )] = (ii) Not possible to say, eg some trapezia are above and some below curve oe. [4] [cannot assume values of form (π/6)³ + (sin π/6) are correct unless followed by correct total at some later stage as some will be in degree mode] Use of the trapezium rule. Trapezium rule formula for 4 strips must be seen, with or without substitution seen. Correct h must be soi. [accept separate trapezia added] www 3dp only (NB using.35 is ww) SC B without any working as no indication of strips or method used SC with some indication of 4 strips but no values seen Correct values followed by scores B B0 Correct values followed by correct formula for 4 strips, with or without substitution seen, then A= scores 4/4. Correct formula for 4 strips and values of form ((π/6)³ + (sinπ/6) followed by correct answer scores 4/4 (or ¾ with wrong dp) NB Values given in the table to only 3dp give apparently the correct answer, but scores B0,A0 ww Need a reason. Must be without further calculation. [] 3

4 4754A Mark Scheme June 04 4 (i) EITHER Use of cos = /sec (or sin= /cosec) From RHS tan tan sec sec sin / cos.sin / cos / cos./ cos sin sin cos cos ( ) cos cos cos cos sin sin Must be used Substituting and simplifying as far as having no fractions within a fraction tt [need more than secsec cc ss ie an intermediate step that can lead to cc ss] cos( ) Convincing simplification and correct use of cos(α + β) Answer given OR From LHS, cos = /sec or sin = /cosec used cos( ) cos cos sin sin sec sec sin sin sec sin sec sin sec sec Correct angle formula and substitution and simplification to one term OR eg cosαcosβ sinαsinβ cos cos ( tan tan ) tan tan sec sec [3] Simplifying to final answer www Answer given Or any equivalent work but must have more than cc ss = answer. 4

5 4754A Mark Scheme June 04 4 (ii) cos tan tan sec tan. β = α used, Need to see sec²α Use of sec²α = + tan²α to give required result Answer Given OR, without Hence, cos cos ( ) sec tan tan ( tan ) sin cos Use of cosα = cos²α sin²α soi Simplifying and using sec²α = + tan²α to final answer Answer Given Accept working in reverse to show RHS=LHS, or showing equivalent 4 (iii) cos = ½ Soi or from tan²θ = /3 oe from sin²θ or cos²θ = 60, 300 = 30, 50 [] [3] First correct solution Second correct solution and no others in the range SC for π/6and 5π/6 and no others in the range 5

6 4754A Mark Scheme June 04 5 (i) EITHER x = e 3t, y = te t soi d / d e e y t x t in terms of t t t y t t Their d / d d / d dy/dx = (te t + e t )/3e 3t oe cao allow for unsimplified form even if subsequently cancelled incorrectly ie can isw when t =, dy/dx = 3e /3e 3 = /e cao www must be simplified to /e oe OR 3t = ln x, y ln e 3 3 /3 x /3ln x x ln x d y / dx x ln x x 3 x 9 /3 /3 = t oe cao t t 3e 3e Any equivalent form of y in terms of x only Differentiating their y provided not eased ie need a product including ln kx and x p and subst x 3 e t to obtain dy/dx in terms of t dy/dx = /3e + /3e =/e www cao exact only must be simplified to /e or e 5 (ii) 3t = ln x t = (ln x)/3 Finding t correctly in terms of x (ln x)/3 y = (ln x ) / 3e Subst in y using their t y = 3 ln 3 x x b Required form ax ln [4] [3] x only NB If this work was already done in 5(i), marks can only be scored in 5(ii) if candidate specifically refers in this part to their part (i). 6

7 4754A Mark Scheme June y ( x ) y x x y 3 finding x (or x) correctly in terms of y ( ) 3 V πx d y π ( y )d y 4 π y y π( ) π 8 [6] For need πx dy with substitution for their x² (in terms of y only) Condone absence of dy throughout if intentions clear. (need π) www For it must be correct with correct limits and, but they may appear later /[y 4 /4 y] independent of π and limits substituting both their limits in correct order in correct expression, condone a minor slip for (if using y = 0 as lower limit then -0 is enough) condone absence of π for oe exact only www (⅜ π or.375π) 7

8 4754A Mark Scheme June 04 7 (i) AB = 5 ( ) or better (condone sign error in vector for ) AC = Accept 5 (condone sign error in vector for ) cos cosθ = scalar product of AB with AC (accept BA/CA) AB. AC with substitution condone a single numerical error provided method is clearly understood [OR Cosine Rule, as far as cos θ= correct numerical expression ] www ± 0.557, 0.557,5/5 9,5/ 5 9 oe or better soi ( ± for method only) = 56.5 www Accept answers that round to 56.º or 56.º or 0.98 radians (or better) NB vector 5i+0j+k leads to apparently correct answer but loses all A marks in part(i) Area = ½ 5 9 sin Using their AB,AC, CAB. Accept any valid method using trigonometry =.8 Accept 5 5 and answers that round to.8 or.9 (dp) www or SC for accurate work soi rounded at the last stage to. (but not from an incorrect answer, say from an incorrect angle or from say.7 or. stated and rounded to.) We will not accept inaccurate work from over rounded answers for the final mark. [7] 8

9 4754A Mark Scheme June 04 7 (ii) (A) AB ( 3) ( ) Scalar product with one vector in the plane with numerical expansion shown AC ( 3) Scalar product, as above, with evaluation, with a second vector. NB vectors are not unique SCB finding the equation of plane first by any valid method (or using vector product) and then clearly stating that the normal is proportional to the coefficients. [] SC For candidates who substitute all three points in the plane 4x-3y+0z = c and show that they give the same result, award If they include a statement explaining why this means that 4i-3j+0k is normal they can gain. 7 (ii) (B) 4x 3y+0z=c Required form and substituting the co-ordinates of a point on the plane 4x 3y + 0z + = 0 oe If found in (A) it must be clearly referred to in (B) to gain the marks. Do not accept vector equation of the plane, as Hence. [] 4i-3j+0k = is A0 9

10 4754A Mark Scheme June 04 7 (iii) 0 r Meets 4x 3y + 0z + = 0 when 6 3(4 3 ) + 0(5 + 0 ) + = 0 5 = 50, = 0.4 Need r = (or oe x y z ) Subst their 4λ, 4 3λ, 5+0λ in equation of their plane from (ii) λ= 0.4 (NB not unique) So meets plane ABC at (.6, 5., ) cao www (condone vector) 7 (iv) height = (.6 + (.) + 4 )= 0 ft ft their (iii) [5] volume =.8 0 / 3 = 6.7 cao 50/3 or answers that round to 6.7 www and not from incorrect answers from (iii) ie not from say (.6,.8,9) [] 0

11 4754A Mark Scheme June 04 8 (i) Either h = ( ½ At) dh/dt = A ( ½ At) Including function of a function, need to see middle step when t = 0, h = ( 0) = as required OR dh h At d = A h AG Separating variables correctly and integrating / h At c Including c. [Condone change of c.] At c h at t =0, h =, = (c/)² c =, h = ( At/)² [3] Using initial conditions AG 8 (ii) When t = 0, h = 0 Subst and solve for A 0 A= 0, A = 0. cao When the depth is 0.5 m, 0.5 = ( 0.05t) substitute h= 0.5 and their A and solve for t 0.05t = 0.5, t = ( 0.5)/0.05 = 5.86s www cao accept 5.9 [4]

12 4754A Mark Scheme June 04 8 (iii) dh h B d t ( h) ( h) d d h EITHER, LHS h h h h B t dh separating variables correctly and intend to integrate both sides (may appear later) [NB reading (+h)²as +h² eases the question. Do not mark as a MR] In cases where (+h)² is MR as +h²or incorrectly expanded, as say +h+h² or +h², allow first for correct separation and attempt to integrate and can then score a max of M0A0A0 (for Bt+c) A0A0, max /7. expanding (+ h) and dividing by h to form a one line function of h (indep of first ) with each term expressed as a single power of h eg must simplify say / h+h/ h +h² h,condone a single error for (do not need to see integral signs) / ( h / h 3/ h )dh h / + h / + h 3/ cao dep on second M only -do not need integral signs OR,LHS, EITHER / / ( h h )h h ( h)dh using udv uv vdu correct formula used correctly, indep of first OR 5/ 3 / 3/ h 3/ h h h h ( h h )dh 3 3 / 4h h h 3 5 3/ 5/ h / + 4h 3/ /3 + h 5/ /5 = Bt + c condone a single error for if intention clear cao oe cao oe, both sides dependent on first mark = Bt +c cao need Bt and c for second but the constant may be on either side When t = 0, h = c = 56/5 from correct work only (accept 3.73 or rounded answers here but not for final ) or c= 56/5 if constant on opposite side. h / (30 + 0h + 6h ) = 56 5Bt * NB AG must be from all correct exact work including exact c. [7]

13 4754A Mark Scheme June 04 8 (iv) h = 0 when t = 0 Substituting h = 0,t = 0 B = 56/300 = 0.87 Accept 0.87 When h = t = Subst their h = 0.5, ft their B and attempt to solve t = 9.5s Accept answers that round to 9.5s www. [4] 3

14 4754B Mark Scheme June 04 (i) for all three entries 30,60,45 correct Group P Q R S Number of people for all three entries.5, 3, 9 correct Average number of accidents in a year for 3000,4500 both correct Average cost of accidents per year SC B for all entries in any three columns correct (ii) Adding their bottom row ( = 4000 and dividing by 50 soi (and not divided or multiplied by any additional values) = 60 ft their (corr to dp if inexact) (iii) The 45 members of Group S pay So each pays [3] [] their oe soi as part of solution = 50. cao www (must be from correct final column) []

15 4754B Mark Scheme June 04 Basic premium = 35% of driver s premium use of 35% or 0.35 oe [not 65, 0.65 unless 0.65] Drivers premium = Basic premium 0.35 =.86 Basic premium k.86 accept.86 or better (k=.8574 or 6 oe) 7 3 Year % discount Total 30 [] [ k =.9, k = /0.35 scores A0 ] obtaining 30 or 3. oe [from adding all relevant terms ie =30 or = 3. soi (with or without first zero term) or from oe] 30% of the premium is 3875 The premium is = cao 3875 their 3. even if one term was missing from addition but must come from attempt at the appropriate addition [ie an error in adding to 30 or an omission of one term, an inclusion of say an extra 65,or an addition of 00,70,60, etc with subsequent subtraction from 700 ] [3]

16 4754B Mark Scheme June 04 4 (i) Percentage Age A sketch. Must be at least for values of x between 8 and 45. Must be correct shape ie descending curve, does not curve up at end, does not cross the horizontal axis (even if extended) ie must. Does not need to go through points exactly as a sketch. 4 (ii) k( x 7) For large values of x, b e 0, and so y awhich is in this case. Need x becoming large or, exponential term 0 oe and y a, a = or y =,a = oe [] [] NOT just at x = 45, y = 4 (iii) Substituting x 3 y 6.6 subst x = 3 and finding y = 6.6 (6.605 ) (or subst y = 6 and finding x = 3.3 ( ) Only accept comparing x or y, not coefficients This is quite close to the observed value of y = 6. (or close to x = 3) Accept say, y = But not say at x = 3, y 6 with no evaluation seen Accept if states, say, y = 6.6 which is not consistent with y = 6 oe [] 3

17 4754B Mark Scheme June 04 5 (A) With no more than 3 points on his licence the driver s premium is not altered: 50 (B) The driver now has = 9 points. The new premium is or 47 [but not ] [] 4

Wednesday 18 June 2014 Afternoon

Wednesday 18 June 2014 Afternoon Wednesday 8 June 04 Afternoon A GCE MATHEMATICS (MEI) 4754/0A Applications of Advanced Mathematics (C4) Paper A QUESTION PAPER * 4 3 4 5 9 5 9 * Candidates answer on the Printed Answer Book. OCR supplied