A-Level Pure Maths Paper 2 Official Unofficial Mark Scheme Question number 1 2 Question Answer a) find f’’(x) b) When is f’’(x) = 0 c) Hence find the range of values for which f(x) is concave ai) Prove that 𝑠2 = 40 a) Marks a) 2 b) 2 Total: 4 6𝑥 + 4 2 3 b) 𝑥 =− c) 𝑥 ≤− 2 3 a) i) Input 𝑥𝑛 and 𝑛 = 1to get 40 aii) Find 𝑠3 and 𝑠4 ii) 𝑠3 = 28 bi) Given that it is periodic with order 4, find the value of 𝑠5 bii) Find sum of first 25 terms 𝑠4 = 33 b) i) 𝑠5 = 35 a) 2 b) 3 Total: 5 ii) 851 can we starts putting marks in 3 Given the following logarithmic equation … 2 a) Prove 3𝑥 − 13𝑥 − 30 = 0 b) Find the roots of the quadratic c) Explain which root is invalid 2 a) 3𝑥 − 13𝑥 − 30 = 0 b) 6 𝑜𝑟 − c) − 5 3 5 3 , as it is negative. a) 2 b) 2 c) 1 Total: 5 4 5 6 7 a) Given the following vectors: 𝑎 = 12𝑗 𝑏 = 16𝑗 𝑐 = 50𝑖 + 136𝑗 d=22𝑖 + 24𝑗 b) ABCD is a track and a runner completes 2 laps in 5 minutes. Find the average speed. Given the following model… And that the: - Temperature is initially 85 - The rate of cooling -7.5 a) Find the value of A b) FInd a full equation for the model a) Show that 𝑘 = 12 b) Find the coordinates when it intersects y axis Partial fractions integration with k a) Express in partial fractions b) Given this integral, find k a) 5𝐴𝐷 = 𝐵𝐶, therefore parallel −1 b) 6. 99 𝑘𝑚ℎ a) 𝐴 = 55 −1.136𝑥 b) 𝐻 = 55𝑒 + 30 a) Show that 𝑘 = 12 b) (0, − 28) a) 2 b) 3 Total: 5 a) 2 b) 2 Total: 4 a) 2 b) 3 Total: 5 2𝑘+3 𝑥+4 𝑘 = , 𝑘−3 𝑥−2 21 𝑙𝑛5 −6 a) 3 b) 5 Total: 8 8 9 Harmonic identity a) Write .. in the form b) Find the minimum value of the function c) Find the value of 𝑥 a) 2 17 𝑐𝑜𝑠(θ − 1. 326) Given the parametric equations a) 𝑦 = 3𝑙𝑛(𝑥 + 25) a) 3 b) 3 c) 3 Total: 9 b) 9 17 c) 𝑥 = 1. 326 2 𝑥 = 𝑡 + 3𝑡 − 16 and 𝑦 = 6𝑙𝑛(𝑡 + 3), with 𝑡 ≥ 3 b) 3𝑥 − 25𝑦 =− 150𝑙𝑛5 a) 3 b) 3 Total: 6 a) Find the cartesian equation b) Find the tangent at… 10 3 2 𝑥 + 2𝑥𝑦 + 3𝑦 = 47 a) Find a) − 𝑑𝑦 𝑑𝑥 a) 3 b) 3 a) Total: 6 2 2𝑦+3𝑥 6𝑦+2𝑐 b) 13𝑥 − 11𝑦 + 81 = 0 b) Find the equation of the normal at the point 𝑃(− 2, 5) Find the normal when P(x,y) 12 Modulus Music companies a) Find the difference in subscribers b) Find the point at which the price change is likely to have occurred, giving a reason for your answer c) Find the range of values where 13 Cuboid with water: ● Height 5m a) 5000 (b) When 𝑡 = 3, because this is when the number of subscribers begins to increase. (c) {𝑡: 0 ≤ 𝑡 ≤ 5 3 } ∪ {𝑡 > 13 3 } (d) It is invalid beyond 𝑡 = 7 because it predicts negative subscribers a) 𝑑ℎ 𝑑𝑡 = λ ℎ (Should get a value of 1/200 at some stage) a) 2 b) 2 c) 5 d) 1 Total: 10 a) 3 b) 5 ● Length 20m ● Width 10m ● Water height h Rate of change of water volume is inversely proportional to √h. a) Show that 𝑑ℎ 𝑑𝑡 = λ ℎ 3 b)ℎ 2 = 0. 513𝑡 + 1. 152 c) 2 Total: 10 c) 18. 4 where λ is a constant. b) Show that h^(3/2)=At+B where A and B are constants to 3 decimal places. c) How long does it take for h to be maximum? 13 Binomial and integration a) Expand.. b) Approximate the integral c) Find the real integral a) 1 9 − 2 27 𝑥+ 1 27 b) 0. 03304 17 c) 6𝑙𝑛( 16 ) − 45 136 2 𝑥 a) 4 b) 4 c) 5 Total: 13 14 a) Trig a) … Given that 2𝑡𝑎𝑛θ(𝑐𝑜𝑠θ − 23…) = 𝑠𝑖𝑛2θ(𝑡𝑎𝑛²θ + 1) b) 360, 49, 540 Show that 14𝑠𝑖𝑛2θ(− 23𝑐𝑜𝑠²θ + 8𝑐𝑜𝑠θ + 15) = 0 b) Hence solve … a) 3 b) 4 Total: 7 15 Proof 2 (𝑐𝑜𝑠𝑥 − 𝑠𝑖𝑛𝑥) < 1 (cosx-sinx)^2<1 cos^2(x)+sin^2(x)-2sin(x)cos(x)<1 1-2sin(x)cos(x)<1 -2sin(x)cos(x)<0 2sin(x)cos(x)><0 sin(2x)><0 Contradiction, for value the sin(2x) contradiction needs to be explained otherwise the proof is incomplete. Sin(2x)>0 is impossible because by the definition of obtuse, x is between 90 and 180 and so 2x is between 180 and 360, let a=2x. So sin(2x)=sin(a) which is negative because from the graph of sin(x), the ranges x at 180 and 360 has sin(x) below the axis. 3 marks