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ZIMSEC A Level · N2018

Pure Mathematics Paper 1 November 2018

Questions
83
Total marks
120

Sit this paper online

Questions
83
Pass mark
50
Sit this paper

Answer every question in the printed order, get marked at the end, then see the answers.

The questions

Question 101

[1 marks]Complex numbers
The equation x3−2x2+4x−8=0x^3 - 2x^2 + 4x - 8 = 0 has a root x=2ix = 2i. Find the other two roots.
  1. Ax=−2ix = -2i and x=2x = 2
  2. Bx=−2ix = -2i and x=−2x = -2
  3. Cx=2ix = 2i and x=2x = 2
  4. Dx=−2ix = -2i and x=4x = 4

Question 102

[2 marks]Complex numbers
Since the coefficients of x3−2x2+4x−8=0x^3-2x^2+4x-8=0 are real, the root x=2ix=2i implies x=−2ix=-2i is also a root, so (x−2i)(x+2i)=x2+4(x-2i)(x+2i)=x^2+4 is a factor. Divide x3−2x2+4x−8x^3-2x^2+4x-8 by x2+4x^2+4 to find the remaining linear factor, in the form x+kx+k. State kk.

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Question 201

[1 marks]Trigonometric equations
Solve cos⁡(θ−75°)=6−24\cos(\theta - 75°) = \dfrac{\sqrt{6}-\sqrt{2}}{4} for 0°≤θ≤360°0° \le \theta \le 360°.
  1. Aθ=0°, 150°, 360°\theta = 0°,\ 150°,\ 360°
  2. Bθ=150°\theta = 150° only
  3. Cθ=15°\theta = 15° and θ=135°\theta = 135°
  4. Dθ=75°\theta = 75° and θ=285°\theta = 285°

Question 202

[2 marks]Trigonometric equations
Recognise that 6−24=cos⁡75°\dfrac{\sqrt6-\sqrt2}{4}=\cos75° (using cos⁡75°=cos⁡(45°+30°)\cos75°=\cos(45°+30°)). Hence rewrite cos⁡(θ−75°)=6−24\cos(\theta-75°)=\dfrac{\sqrt6-\sqrt2}{4} in the form cos⁡(θ−75°)=cos⁡ϕ°\cos(\theta-75°)=\cos\phi°. State ϕ\phi.

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Question 301

[1 marks]Simultaneous equations
Solve the simultaneous equations e2x+y=1e^{2x+y} = 1 and 4x−3y=104x - 3y = 10.
  1. Ax=2x = 2, y=−1y = -1
  2. Bx=52x = \tfrac{5}{2}, y=0y = 0
  3. Cx=1x = 1, y=−2y = -2
  4. Dx=−1x = -1, y=2y = 2

Question 302

[2 marks]Simultaneous equations
Taking natural logs of e2x+y=1e^{2x+y}=1 gives 2x+y=02x+y=0. Substitute y=−2xy=-2x into 4x−3y=104x-3y=10 and simplify to find xx.

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Question 401

[1 marks]Inequalities
Solve the inequality 21+13x2+3x2≥10\dfrac{21+13x}{2+3x^2} \ge 10.
  1. A−12≤x≤115-\tfrac{1}{2} \le x \le \tfrac{1}{15}
  2. B−115≤x≤12-\tfrac{1}{15} \le x \le \tfrac{1}{2}
  3. Cx≥12x \ge \tfrac{1}{2} only
  4. Dx≤−115x \le -\tfrac{1}{15} or x≥12x \ge \tfrac{1}{2}

Question 402

[2 marks]Inequalities
Since 2+3x2>02+3x^2>0 for all xx, multiplying both sides of 21+13x2+3x2≥10\dfrac{21+13x}{2+3x^2}\ge10 by 2+3x22+3x^2 and simplifying gives an inequality of the form 30x2+bx+c≤030x^2+bx+c\le0. State bb and cc.

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Question 403

[1 marks]Inequalities
Solve 30x2−13x−1=030x^2-13x-1=0 using the quadratic formula. State the larger root.

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Question 501

[1 marks]Implicit differentiation
A curve has equation y2=3xy+x2−3y^2 = 3xy + x^2 - 3. Find dydx\dfrac{dy}{dx}.
  1. A3y+2x2y−3x\dfrac{3y + 2x}{2y - 3x}
  2. B2y−3x3y+2x\dfrac{2y - 3x}{3y + 2x}
  3. C3y−2x2y+3x\dfrac{3y - 2x}{2y + 3x}
  4. D3x+2y2x−3y\dfrac{3x + 2y}{2x - 3y}

Question 502

[1 marks]Implicit differentiation
Find the equation of the tangent to y2=3xy+x2−3y^2 = 3xy + x^2 - 3 at the point where y=1y = 1 and x>0x > 0.
  1. Ay=−5x−6y = -5x - 6
  2. By=5x−4y = 5x - 4
  3. Cy=−5x+6y = -5x + 6
  4. Dy=−15x+65y = -\tfrac{1}{5}x + \tfrac{6}{5}

Question 503

[2 marks]Implicit differentiation
Substitute y=1y=1 into y2=3xy+x2−3y^2=3xy+x^2-3 to find the value(s) of xx, giving your answer(s) as solutions of a quadratic x2+bx+c=0x^2+bx+c=0. State bb and cc.

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Question 504

[1 marks]Implicit differentiation
Factorise x2+3x−4x^2+3x-4.

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Question 505

[1 marks]Implicit differentiation
Since x>0x>0, state the xx-coordinate of the point on the curve y2=3xy+x2−3y^2=3xy+x^2-3 where y=1y=1.

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Question 506

[2 marks]Implicit differentiation
Using implicit differentiation on y2=3xy+x2−3y^2=3xy+x^2-3, find dydx\dfrac{dy}{dx} in the form 3y+2x2y−Kx\dfrac{3y+2x}{2y-Kx}. State KK.

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Question 601

[1 marks]Functions and inverses
Express f(x)=−x2+8x−12f(x) = -x^2 + 8x - 12 in the form a(x+b)2+ca(x+b)^2 + c.
  1. A−(x+4)2+4-(x+4)^2 + 4
  2. B(x−4)2−4(x-4)^2 - 4
  3. C−(x−4)2−4-(x-4)^2 - 4
  4. D−(x−4)2+4-(x-4)^2 + 4

Question 602

[1 marks]Functions and inverses
The function f(x)=−x2+8x−12f(x) = -x^2 + 8x - 12 is defined for 4≤x≤64 \le x \le 6. Find f−1(x)f^{-1}(x) and state its domain.
  1. Af−1(x)=4+4−xf^{-1}(x) = 4 + \sqrt{4-x}, domain 0≤x≤40 \le x \le 4
  2. Bf−1(x)=4−4−xf^{-1}(x) = 4 - \sqrt{4-x}, domain 0≤x≤40 \le x \le 4
  3. Cf−1(x)=4+4−xf^{-1}(x) = 4 + \sqrt{4-x}, domain 4≤x≤64 \le x \le 6
  4. Df−1(x)=4+x−4f^{-1}(x) = 4 + \sqrt{x-4}, domain x≥4x \ge 4

Question 603

[2 marks]Functions and inverses
Which of the following explains why f(x)=−x2+8x−12f(x)=-x^2+8x-12 has an inverse on the domain 4≤x≤64\le x\le6?
  1. Aff is strictly increasing on [4,6][4,6] because f′(x)=8−2x≥0f'(x)=8-2x\ge0 there.
  2. Bff is strictly decreasing on [4,6][4,6] because f′(x)=8−2x≤0f'(x)=8-2x\le0 there.
  3. CThe vertex of ff lies outside the interval [4,6][4,6], so no repeated yy-values occur.
  4. Df(4)f(4) and f(6)f(6) are both positive, so ff cannot repeat a value.

Question 604

[2 marks]Functions and inverses
The graphs of y=f(x)y=f(x) and y=f−1(x)y=f^{-1}(x) meet the line y=xy=x where f(x)=xf(x)=x. Solve −x2+8x−12=x-x^2+8x-12=x to find both solutions of the resulting quadratic (only one lies in the domain [4,6][4,6]).

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Question 605

[1 marks]Functions and inverses
Which of the solutions of −x2+8x−12=x-x^2+8x-12=x lies within the domain 4≤x≤64\le x\le6, and is therefore the point where the graphs of y=f(x)y=f(x) and y=f−1(x)y=f^{-1}(x) intersect?

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Question 606

[1 marks]Functions and inverses
State the range of f(x)=−x2+8x−12f(x)=-x^2+8x-12 on 4≤x≤64\le x\le6 (needed to know where y=f−1(x)y=f^{-1}(x) starts and ends on the sketch).

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Question 701

[1 marks]Complex numbers
The complex number uu satisfies −48+56iu=1+13i\dfrac{-48+56i}{u} = 1 + 13i. Express uu in the form a+iba + ib.
  1. A−4+4i-4 + 4i
  2. B8+8i8 + 8i
  3. C4−4i4 - 4i
  4. D4+4i4 + 4i

Question 702

[1 marks]Complex numbers
Given u=4+4iu = 4 + 4i, state its modulus and argument.
  1. A∣u∣=42|u| = 4\sqrt{2}, arg⁡u=−π4\arg u = -\tfrac{\pi}{4}
  2. B∣u∣=42|u| = 4\sqrt{2}, arg⁡u=π4\arg u = \tfrac{\pi}{4}
  3. C∣u∣=4|u| = 4, arg⁡u=π2\arg u = \tfrac{\pi}{2}
  4. D∣u∣=8|u| = 8, arg⁡u=π4\arg u = \tfrac{\pi}{4}

Question 703

[2 marks]Complex numbers
To find u=−48+56i1+13iu=\dfrac{-48+56i}{1+13i}, multiply numerator and denominator by the conjugate 1−13i1-13i. Find the denominator (1+13i)(1−13i)(1+13i)(1-13i).

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Question 704

[2 marks]Complex numbers
Find the numerator (−48+56i)(1−13i)(-48+56i)(1-13i), in the form p+qip+qi.

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Question 705

[1 marks]Complex numbers
Given u=4+4iu=4+4i, write down the complex conjugate u∗u^*.

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Question 706

[1 marks]Complex numbers
State the modulus of u∗=4−4iu^*=4-4i, in exact surd form.

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Question 801

[1 marks]Integration by parts and volumes of revolution
Find ∫xe−2x dx\displaystyle\int xe^{-2x}\,dx.
  1. A−12xe−2x−14e−2x+c-\tfrac{1}{2}xe^{-2x} - \tfrac{1}{4}e^{-2x} + c
  2. B−12xe−2x+14e−2x+c-\tfrac{1}{2}xe^{-2x} + \tfrac{1}{4}e^{-2x} + c
  3. C12xe−2x−14e−2x+c\tfrac{1}{2}xe^{-2x} - \tfrac{1}{4}e^{-2x} + c
  4. D−12x2e−2x+c-\tfrac{1}{2}x^2e^{-2x} + c

Question 802

[1 marks]Integration by parts and volumes of revolution
The region bounded by y=2x+e−2xy = 2x + e^{-2x}, the xx-axis and the lines x=0x = 0 and x=1x = 1 is rotated completely about the xx-axis. Find the volume, correct to 3 significant figures.
  1. A2.172.17
  2. B4.504.50
  3. C4.964.96
  4. D6.836.83

Question 803

[2 marks]Integration by parts and volumes of revolution
Using integration by parts on ∫xe−2x dx\int xe^{-2x}\,dx with u=xu=x, dv=e−2xdxdv=e^{-2x}dx, state vv (the antiderivative of e−2xe^{-2x}).

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Question 804

[2 marks]Integration by parts and volumes of revolution
Expand (2x+e−2x)2(2x+e^{-2x})^2 (needed for the volume integral π∫01y2 dx\pi\int_0^1y^2\,dx), giving the answer in the form 4x2+Axe−2x+e−4x4x^2+Axe^{-2x}+e^{-4x}. State AA.

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Question 805

[1 marks]Integration by parts and volumes of revolution
Evaluate ∫014x2 dx\displaystyle\int_0^1 4x^2\,dx, as an exact fraction.

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Question 806

[2 marks]Integration by parts and volumes of revolution
Evaluate ∫01e−4x dx\displaystyle\int_0^1 e^{-4x}\,dx, correct to 4 decimal places.

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Question 901

[1 marks]Partial fractions and integration
Express f(x)=15x2+40x+2(4+x)(2+5x2)f(x) = \dfrac{15x^2 + 40x + 2}{(4+x)(2+5x^2)} in partial fractions.
  1. A14+x−10x2+5x2\dfrac{1}{4+x} - \dfrac{10x}{2+5x^2}
  2. B14+x+10x+22+5x2\dfrac{1}{4+x} + \dfrac{10x + 2}{2+5x^2}
  3. C14+x+10x2+5x2\dfrac{1}{4+x} + \dfrac{10x}{2+5x^2}
  4. D104+x+x2+5x2\dfrac{10}{4+x} + \dfrac{x}{2+5x^2}

Question 902

[1 marks]Partial fractions and integration
Evaluate ∫02(14+x+10x2+5x2)dx\displaystyle\int_0^2 \left(\dfrac{1}{4+x} + \dfrac{10x}{2+5x^2}\right)dx, giving your answer as a single logarithm.
  1. Aln⁡132\ln 132
  2. Bln⁡332\ln\tfrac{33}{2}
  3. Cln⁡112\ln\tfrac{11}{2}
  4. Dln⁡233\ln\tfrac{2}{33}

Question 903

[2 marks]Partial fractions and integration
Using the cover-up rule, evaluate A=15x2+40x+22+5x2A=\dfrac{15x^2+40x+2}{2+5x^2} at x=−4x=-4 (the root of 4+x4+x), to find the coefficient AA in A4+x+Bx+C2+5x2\dfrac{A}{4+x}+\dfrac{Bx+C}{2+5x^2}.

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Question 904

[2 marks]Partial fractions and integration
Comparing coefficients of x2x^2 in 15x2+40x+2≡A(2+5x2)+(Bx+C)(4+x)15x^2+40x+2\equiv A(2+5x^2)+(Bx+C)(4+x), with A=1A=1: 5A+B=155A+B=15. Find BB.

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Question 905

[1 marks]Partial fractions and integration
Comparing the constant terms in 15x2+40x+2≡A(2+5x2)+(Bx+C)(4+x)15x^2+40x+2\equiv A(2+5x^2)+(Bx+C)(4+x): 2A+4C=22A+4C=2. With A=1A=1, find CC.

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Question 906

[2 marks]Partial fractions and integration
The antiderivative ln⁡(4+x)+ln⁡(2+5x2)\ln(4+x)+\ln(2+5x^2) combines into a single log, ln⁡[(4+x)(2+5x2)]\ln[(4+x)(2+5x^2)]. State the argument of this logarithm (the numeric value inside) at x=2x=2.

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Question 1001

[1 marks]Vectors
OA→=−4λi−3λj+4λk\overrightarrow{OA} = -4\lambda\mathbf{i} - 3\lambda\mathbf{j} + 4\lambda\mathbf{k} and OB→=3i+9j−6k\overrightarrow{OB} = 3\mathbf{i} + 9\mathbf{j} - 6\mathbf{k}. Given that AB→\overrightarrow{AB} is perpendicular to OB→\overrightarrow{OB}, find λ\lambda.
  1. Aλ=−2\lambda = -2
  2. Bλ=−12\lambda = -\tfrac{1}{2}
  3. Cλ=63\lambda = 63
  4. Dλ=2\lambda = 2

Question 1002

[1 marks]Vectors
With OA→=(8,6,−8)\overrightarrow{OA} = (8, 6, -8) and OB→=(3,9,−6)\overrightarrow{OB} = (3, 9, -6), find angle AO^BA\hat{O}B correct to the nearest 0.1°0.1°.
  1. A61.3°61.3°
  2. B90.0°90.0°
  3. C151.3°151.3°
  4. D28.7°28.7°

Question 1003

[1 marks]Vectors
OO, A(8,6,−8)A(8, 6, -8) and BB lie on a circle in which angle OBA=90°OBA = 90°. Find the centre and radius of the circle.
  1. Acentre (4,3,−4)(4, 3, -4), radius 2412\sqrt{41}
  2. Bcentre (4,3,−4)(4, 3, -4), radius 4141
  3. Ccentre (4,3,−4)(4, 3, -4), radius 41\sqrt{41}
  4. Dcentre (8,6,−8)(8, 6, -8), radius 2412\sqrt{41}

Question 1004

[2 marks]Vectors
Form AB→=OB→−OA→=(3+4λ)i+(9+3λ)j+(−6−4λ)k\overrightarrow{AB}=\overrightarrow{OB}-\overrightarrow{OA}=(3+4\lambda)\mathbf{i}+(9+3\lambda)\mathbf{j}+(-6-4\lambda)\mathbf{k}. Using AB→⋅OB→=0\overrightarrow{AB}\cdot\overrightarrow{OB}=0, simplify to a linear equation in λ\lambda, in the form 63λ=k63\lambda=k. State kk.

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Question 1005

[2 marks]Vectors
Find OA→⋅OB→\overrightarrow{OA}\cdot\overrightarrow{OB} for OA→=8i+6j−8k\overrightarrow{OA}=8\mathbf{i}+6\mathbf{j}-8\mathbf{k} and OB→=3i+9j−6k\overrightarrow{OB}=3\mathbf{i}+9\mathbf{j}-6\mathbf{k}.

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Question 1006

[2 marks]Vectors
Since ∠OBA=90°\angle OBA=90°, OAOA is a diameter of the circle through OO, A(8,6,−8)A(8,6,-8) and BB. State the coordinates of the midpoint of OAOA (the centre of the circle).

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Question 1101

[1 marks]Binomial expansion
In the expansion of (1+ax)n(1+ax)^n with n<0n < 0, the coefficients of xx and x3x^3 are −1-1 and −143-\tfrac{14}{3}. Find nn.
  1. An=−3n = -3
  2. Bn=−13n = -\tfrac{1}{3}
  3. Cn=−29n = -\tfrac{2}{9}
  4. Dn=29n = \tfrac{2}{9}

Question 1102

[1 marks]Binomial expansion
In the expansion of (1+ax)n(1+ax)^n with n=−13n = -\tfrac{1}{3} and the coefficient of xx equal to −1-1, find aa and the set of values of xx for which the expansion is valid.
  1. Aa=−3a = -3, valid for ∣x∣<13|x| < \tfrac{1}{3}
  2. Ba=3a = 3, valid for ∣x∣<3|x| < 3
  3. Ca=13a = \tfrac{1}{3}, valid for ∣x∣<3|x| < 3
  4. Da=3a = 3, valid for ∣x∣<13|x| < \tfrac{1}{3}

Question 1103

[2 marks]Binomial expansion
In the expansion of (1+ax)n(1+ax)^n, the coefficient of xx is na=−1na=-1, so a=−1na=-\dfrac1n. The coefficient of x3x^3, n(n−1)(n−2)6a3=−143\dfrac{n(n-1)(n-2)}{6}a^3=-\dfrac{14}{3}, becomes −(n−1)(n−2)6n2=−143-\dfrac{(n-1)(n-2)}{6n^2}=-\dfrac{14}{3} after substituting a=−1na=-\tfrac1n. Simplify to (n−1)(n−2)=kn2(n-1)(n-2)=kn^2. Find kk.

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Question 1104

[2 marks]Binomial expansion
Expand (n−1)(n−2)(n-1)(n-2), in the form n2+bn+cn^2+bn+c.

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Question 1105

[1 marks]Binomial expansion
Solve 27n2+3n−2=027n^2+3n-2=0 using the quadratic formula. Find the discriminant 32−4(27)(−2)3^2-4(27)(-2).

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Question 1106

[2 marks]Binomial expansion
Using the discriminant 225225 (so 225=15\sqrt{225}=15), find the positive root n=−3+1554n=\dfrac{-3+15}{54} of 27n2+3n−2=027n^2+3n-2=0 (not the required negative root, n<0n<0).

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Question 1201

[1 marks]Numerical methods (Newton-Raphson)
For f(x)=x3−4ex/2f(x) = x^3 - 4e^{x/2}, the Newton-Raphson iterative formula for a root of f(x)=0f(x) = 0 is
  1. Axn+1=xn−xn3−4exn/23xn2−4exn/2x_{n+1} = x_n - \dfrac{x_n^3 - 4e^{x_n/2}}{3x_n^2 - 4e^{x_n/2}}
  2. Bxn+1=xn−xn3−4exn/23xn2−2exn/2x_{n+1} = x_n - \dfrac{x_n^3 - 4e^{x_n/2}}{3x_n^2 - 2e^{x_n/2}}
  3. Cxn+1=xn−3xn2−2exn/2xn3−4exn/2x_{n+1} = x_n - \dfrac{3x_n^2 - 2e^{x_n/2}}{x_n^3 - 4e^{x_n/2}}
  4. Dxn+1=xn+xn3−4exn/23xn2−2exn/2x_{n+1} = x_n + \dfrac{x_n^3 - 4e^{x_n/2}}{3x_n^2 - 2e^{x_n/2}}

Question 1202

[1 marks]Numerical methods (Newton-Raphson)
Taking x1=2x_1 = 2, use the Newton-Raphson formula for x3−4ex/2=0x^3 - 4e^{x/2} = 0 to find x2x_2 correct to 3 decimal places.
  1. A1.9001.900
  2. B2.3482.348
  3. C2.4382.438
  4. D2.5002.500

Question 1203

[2 marks]Numerical methods (Newton-Raphson)
Evaluate f(1,9)=1,93−4e0,95f(1{,}9)=1{,}9^3-4e^{0{,}95}, correct to 3 decimal places (used to verify the root lies between 1.9 and 2.5).

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Question 1204

[2 marks]Numerical methods (Newton-Raphson)
Evaluate f(2,5)=2,53−4e1,25f(2{,}5)=2{,}5^3-4e^{1{,}25}, correct to 3 decimal places.

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Question 1205

[2 marks]Numerical methods (Newton-Raphson)
Find f′(x)=3x2−2ex/2f'(x)=3x^2-2e^{x/2} evaluated at x=2x=2, correct to 3 decimal places (the denominator of the Newton-Raphson formula at x1=2x_1=2).

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Question 1206

[1 marks]Numerical methods (Newton-Raphson)
Find f(2)=23−4e1f(2)=2^3-4e^1, correct to 3 decimal places (the numerator of the Newton-Raphson formula at x1=2x_1=2).

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Question 1301

[1 marks]Arithmetic and geometric progressions
In an arithmetic progression the sum of the 5th and 10th terms is 27 and the 3rd term is −9-9. Find the first term and common difference.
  1. Aa=19a = 19, d=−5d = -5
  2. Ba=−9a = -9, d=5d = 5
  3. Ca=−19a = -19, d=−5d = -5
  4. Da=−19a = -19, d=5d = 5

Question 1302

[1 marks]Arithmetic and geometric progressions
An arithmetic progression has a=−19a = -19 and d=5d = 5. Find the smallest value of nn for which the sum of the first nn terms is positive.
  1. An=8n = 8
  2. Bn=10n = 10
  3. Cn=9n = 9
  4. Dn=43n = 43

Question 1303

[1 marks]Arithmetic and geometric progressions
A geometric progression with r<0r < 0 has 4th term 2.562.56 and 6th term 1.63481.6348. Find its sum to infinity, correct to 2 decimal places.
  1. A−27.78-27.78
  2. B−5.00-5.00
  3. C−2.78-2.78
  4. D2.782.78

Question 1304

[3 marks]Arithmetic and geometric progressions
Using the first term a=−19a=-19 and common difference d=5d=5 of the arithmetic progression, find S9S_9 (the sum of the first 9 terms), using Sn=n2(2a+(n−1)d)S_n=\tfrac n2(2a+(n-1)d).

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Question 1305

[1 marks]Arithmetic and geometric progressions
Find S8S_8 (the sum of the first 8 terms), and confirm it is not yet positive.

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Question 1306

[1 marks]Arithmetic and geometric progressions
Using r2=1.63482.56≈0,6386r^2=\dfrac{1.6348}{2.56}\approx0{,}6386, giving r≈−0,8r\approx-0{,}8, and ar3=2,56ar^3=2{,}56, find r3r^3.

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Question 1307

[1 marks]Arithmetic and geometric progressions
Hence find a=2.56r3a=\dfrac{2.56}{r^3} using r3=−0,512r^3=-0{,}512.

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Question 1308

[1 marks]Arithmetic and geometric progressions
State ∣r∣|r| for r=−0,8r=-0{,}8, used to confirm ∣r∣<1|r|<1 so the sum to infinity exists.

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Question 1309

[2 marks]Arithmetic and geometric progressions
Find T5=a+4dT_5=a+4d and T10=a+9dT_{10}=a+9d using a=−19a=-19, d=5d=5.

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Question 1401

[1 marks]Coordinate geometry of the circle
A circle has centre A(−3,k)A(-3, k) and the tangent at B(3,3k)B(3, 3k) has gradient −34-\tfrac{3}{4}. Find kk.
  1. Ak=−4k = -4
  2. Bk=8k = 8
  3. Ck=4k = 4
  4. Dk=3k = 3

Question 1402

[1 marks]Coordinate geometry of the circle
A circle has centre A(−3,4)A(-3, 4) and passes through B(3,12)B(3, 12). Find its equation.
  1. A(x+3)2+(y−4)2=100(x+3)^2 + (y-4)^2 = 100
  2. B(x+3)2+(y+4)2=100(x+3)^2 + (y+4)^2 = 100
  3. C(x+3)2+(y−4)2=10(x+3)^2 + (y-4)^2 = 10
  4. D(x−3)2+(y−4)2=100(x-3)^2 + (y-4)^2 = 100

Question 1403

[1 marks]Coordinate geometry of the circle
The circle (x+3)2+(y−4)2=100(x+3)^2 + (y-4)^2 = 100 crosses the xx-axis. Find the xx-coordinates of the crossing points, correct to 2 decimal places.
  1. Ax=−9.17x = -9.17 and x=3.17x = 3.17
  2. Bx=−10.00x = -10.00 and x=10.00x = 10.00
  3. Cx=−12.17x = -12.17 and x=6.17x = 6.17
  4. Dx=−6.17x = -6.17 and x=12.17x = 12.17

Question 1404

[2 marks]Coordinate geometry of the circle
The perpendicular distance from the centre A(−3,4)A(-3,4) to the xx-axis is d=4d=4. With radius r=10r=10, find cos⁡θ=dr\cos\theta=\dfrac{d}{r}, where 2θ2\theta is the central angle subtended by the chord (the xx-axis intercepts).

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Question 1405

[2 marks]Coordinate geometry of the circle
Find θ=arccos⁡(0,4)\theta=\arccos(0{,}4), in radians, correct to 4 decimal places.

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Question 1406

[2 marks]Coordinate geometry of the circle
Hence find the central angle α=2θ\alpha=2\theta subtended by the chord, in radians, correct to 4 decimal places.

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Question 1407

[2 marks]Coordinate geometry of the circle
Find sin⁡α\sin\alpha for α=2,3186\alpha=2{,}3186 radians, correct to 4 decimal places (needed for the segment area formula).

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Question 1408

[2 marks]Coordinate geometry of the circle
Using the segment area formula Area=12r2(α−sin⁡α)\text{Area}=\tfrac12r^2(\alpha-\sin\alpha) with r=10r=10, α=2,3186\alpha=2{,}3186, sin⁡α=0,7332\sin\alpha=0{,}7332, find the area of the minor segment cut off by the xx-axis, correct to 3 significant figures.

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Question 1501

[1 marks]Differentiation and curve sketching
The function f(x)=132x+12(x−3)−1f(x) = \tfrac{1}{32}x + \tfrac{1}{2}(x-3)^{-1} is defined for x≠kx \ne k. State the value of kk and find the xx-coordinates of the turning points.
  1. Ak=0k = 0; turning points at x=−1x = -1 and x=7x = 7
  2. Bk=3k = 3; turning points at x=1x = 1 and x=−7x = -7
  3. Ck=3k = 3; turning point at x=3x = 3 only
  4. Dk=3k = 3; turning points at x=−1x = -1 and x=7x = 7

Question 1502

[1 marks]Differentiation and curve sketching
For f(x)=132x+12(x−3)−1f(x) = \tfrac{1}{32}x + \tfrac{1}{2}(x-3)^{-1}, state the turning points and their nature.
  1. A(−1,−532)\left(-1, -\tfrac{5}{32}\right) minimum and (7,1132)\left(7, \tfrac{11}{32}\right) maximum
  2. B(−1,−532)\left(-1, -\tfrac{5}{32}\right) maximum and (7,1132)\left(7, \tfrac{11}{32}\right) minimum
  3. C(−1,532)\left(-1, \tfrac{5}{32}\right) maximum and (7,−1132)\left(7, -\tfrac{11}{32}\right) minimum
  4. Dboth are points of inflexion

Question 1503

[1 marks]Differentiation and curve sketching
Show that the graph of f(x)=132x+12(x−3)−1f(x) = \tfrac{1}{32}x + \tfrac{1}{2}(x-3)^{-1} does not cross the xx-axis. Which reason is correct?
  1. Af(x)=0f(x) = 0 leads to x2+3x−16=0x^2 + 3x - 16 = 0, which has no integer roots
  2. BThe function is always positive
  3. CThe function has a vertical asymptote at x=3x = 3
  4. Df(x)=0f(x) = 0 leads to x2−3x+16=0x^2 - 3x + 16 = 0, whose discriminant is −55<0-55 < 0

Question 1504

[2 marks]Differentiation and curve sketching
Differentiate f(x)=132x+12(x−3)−1f(x)=\dfrac1{32}x+\dfrac12(x-3)^{-1} to find f′(x)f'(x), in the form 132−12(x−3)−K\dfrac1{32}-\dfrac12(x-3)^{-K}. State KK.

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Question 1505

[2 marks]Differentiation and curve sketching
Setting f′(x)=0f'(x)=0: 132=12(x−3)2\dfrac1{32}=\dfrac1{2(x-3)^2} gives (x−3)2=16(x-3)^2=16. Solve for xx, stating both values.

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Question 1506

[1 marks]Differentiation and curve sketching
Find f(7)f(7), as an exact fraction (the yy-coordinate of one turning point).

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Question 1507

[1 marks]Differentiation and curve sketching
Find f(−1)f(-1), as an exact fraction (the yy-coordinate of the other turning point).

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Question 1508

[2 marks]Differentiation and curve sketching
Find f′′(x)f''(x), in the form (x−3)−K(x-3)^{-K}. State KK.

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Question 1509

[2 marks]Differentiation and curve sketching
Evaluate f′′(7)f''(7), as an exact fraction (used to determine the nature of the turning point at x=7x=7).

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