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ZIMSEC A Level · N2009

Pure Mathematics Paper 1 November 2009

Questions
77
Total marks
120

Sit this paper online

Questions
77
Pass mark
47
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]binomial expansion
In the expansion of (x2−2x)9\left(x^2 - \dfrac{2}{x}\right)^9, what is the coefficient of x−3x^{-3}?
  1. A−10752-10752
  2. B−4608-4608
  3. C−2304-2304
  4. D46084608

Question 102

[3 marks]binomial expansion
In the expansion of (x2−2x)9\left(x^2-\dfrac2x\right)^9, the general term is (9r)(x2)9−r(−2x)r=(9r)(−2)rx18−3r\binom{9}{r}(x^2)^{9-r}\left(-\dfrac2x\right)^r=\binom9r(-2)^rx^{18-3r}. For the x−3x^{-3} term, solve 18−3r=−318-3r=-3 for rr.

Answer this when you sit the paper.

Question 201

[1 marks]trigonometry, cosine rule
In triangle ABCABC, AC=7AC=7 cm, CB=3CB=3 cm and AB^C=60°A\hat{B}C=60°. Writing AB=cAB=c and applying the cosine rule at vertex BB, AC2=AB2+CB2−2⋅AB⋅CBcos⁡BAC^2=AB^2+CB^2-2\cdot AB\cdot CB\cos B, find the length of ABAB.
  1. A1616 cm
  2. B55 cm
  3. C−5-5 cm
  4. D88 cm

Question 202

[2 marks]trigonometry, cosine rule
In triangle ABCABC with AC=7AC=7, CB=3CB=3, angle B=60°B=60°, the cosine rule AC2=AB2+CB2−2⋅AB⋅CBcos⁡BAC^2=AB^2+CB^2-2\cdot AB\cdot CB\cos B gives a quadratic equation in ABAB (writing c=ABc=AB), in the form c2−3c−k=0c^2-3c-k=0. State kk.

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Question 203

[2 marks]trigonometry, cosine rule
Using AB=8AB=8 (found from AC=7AC=7, CB=3CB=3, angle B=60°B=60°), evaluate the numerator AC2+CB2−AB2AC^2+CB^2-AB^2 used in cos⁡C=AC2+CB2−AB22⋅AC⋅CB\cos C=\dfrac{AC^2+CB^2-AB^2}{2\cdot AC\cdot CB}.

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Question 301

[1 marks]partial fractions
Writing 5x2+7x+9(x+2)2(3−x)=Ax+2+B(x+2)2+C3−x\dfrac{5x^2+7x+9}{(x+2)^2(3-x)}=\dfrac{A}{x+2}+\dfrac{B}{(x+2)^2}+\dfrac{C}{3-x}, so that 5x2+7x+9=A(x+2)(3−x)+B(3−x)+C(x+2)25x^2+7x+9=A(x+2)(3-x)+B(3-x)+C(x+2)^2, what is the value of BB, found by substituting x=−2x=-2?
  1. A−3-3
  2. B33
  3. C55
  4. D1515

Question 302

[1 marks]partial fractions
Express 5x2+7x+9(x+2)2(3−x)\dfrac{5x^2+7x+9}{(x+2)^2(3-x)} in partial fractions.
  1. A−2x+2+3(x+2)2−33−x\dfrac{-2}{x+2}+\dfrac{3}{(x+2)^2}-\dfrac{3}{3-x}
  2. B8x+2+3(x+2)2+33−x\dfrac{8}{x+2}+\dfrac{3}{(x+2)^2}+\dfrac{3}{3-x}
  3. C−2x+2+3(x+2)2+33−x\dfrac{-2}{x+2}+\dfrac{3}{(x+2)^2}+\dfrac{3}{3-x}
  4. D2x+2+3(x+2)2+33−x\dfrac{2}{x+2}+\dfrac{3}{(x+2)^2}+\dfrac{3}{3-x}

Question 303

[3 marks]partial fractions
Comparing coefficients of x2x^2 in 5x2+7x+9=A(x+2)(3−x)+B(3−x)+C(x+2)25x^2+7x+9=A(x+2)(3-x)+B(3-x)+C(x+2)^2 gives 5=−A+C5=-A+C. Given C=3C=3 (found by substituting x=3x=3), state AA.

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Question 401

[1 marks]functions
The function ff is defined by f:x→1+x2xf:x\to\dfrac{1+x^2}{x}, x∈Rx\in\mathbb{R}, x≠kx\neq k. State the value of kk.

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Question 402

[1 marks]functions
Given f(x)=1+x2xf(x)=\dfrac{1+x^2}{x} (x≠0x\neq 0), find f ⁣(1x)f\!\left(\dfrac{1}{x}\right) in its simplest form.
  1. A1−x2x\dfrac{1-x^2}{x}
  2. Bx2+1x2\dfrac{x^2+1}{x^2}
  3. C1+x2x\dfrac{1+x^2}{x}
  4. Dx2+1x^2+1

Question 403

[1 marks]functions
Given f(x)=1+x2xf(x)=\dfrac{1+x^2}{x} (x≠0x\neq0), find the other element in the domain (besides x=2x=2) that has the same image as x=2x=2.
  1. A−2-2
  2. B12\dfrac12
  3. C−12-\dfrac12
  4. D11

Question 404

[3 marks]functions
Setting f(x)=52f(x)=\dfrac52 (the image of x=2x=2 under f(x)=1+x2xf(x)=\dfrac{1+x^2}x) gives the quadratic 2x2−5x+2=02x^2-5x+2=0, which factorises as (2x−1)(x−c)=0(2x-1)(x-c)=0. State cc.

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Question 501

[1 marks]complex numbers
Given z=−3+2iz=-3+2i, find ∣z∣|z|.
  1. A13\sqrt{13}
  2. B55
  3. C5\sqrt5
  4. D1313

Question 502

[1 marks]complex numbers
Given z=−3+2iz=-3+2i, find arg⁡z\arg z (to 1 decimal place).
  1. A146.3°146.3°
  2. B33.7°33.7°
  3. C−146.3°-146.3°
  4. D213.7°213.7°

Question 503

[1 marks]complex numbers
Given z=−3+2iz=-3+2i and w=5+4iw=5+4i, find zw\dfrac{z}{w} in the form a+iba+ib.
  1. A−79+229i-\dfrac{7}{9}+\dfrac{22}{9}i
  2. B−741+2241i-\dfrac{7}{41}+\dfrac{22}{41}i
  3. C−741−2241i-\dfrac{7}{41}-\dfrac{22}{41}i
  4. D741+2241i\dfrac{7}{41}+\dfrac{22}{41}i

Question 504

[3 marks]complex numbers
Multiplying −3+2i5+4i\dfrac{-3+2i}{5+4i} by 5−4i5−4i\dfrac{5-4i}{5-4i}, state the numerator (−3+2i)(5−4i)(-3+2i)(5-4i) in the form a+bia+bi (before dividing by the denominator 41).

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Question 601

[1 marks]polynomials
Given that (3x−2)(3x-2) is a factor of 6x3+8x2+kx+26x^3+8x^2+kx+2, find the value of kk.
  1. A−11-11
  2. B−9-9
  3. C−8-8
  4. D1111

Question 602

[1 marks]polynomials
Given that k=−11k=-11, so that 6x3+8x2−11x+2=6x3+8x2+kx+26x^3+8x^2-11x+2=6x^3+8x^2+kx+2 has (3x−2)(3x-2) as a factor and quotient 2x2+4x−12x^2+4x-1, what are the roots of 2x2+4x−1=02x^2+4x-1=0?
  1. A−2+62\dfrac{-2+\sqrt6}{2} and −2−62\dfrac{-2-\sqrt6}{2}
  2. B−4+64\dfrac{-4+\sqrt6}{4} and −4−64\dfrac{-4-\sqrt6}{4}
  3. C−2+6-2+\sqrt6 and −2−6-2-\sqrt6
  4. D2+62\dfrac{2+\sqrt6}{2} and 2−62\dfrac{2-\sqrt6}{2}

Question 603

[2 marks]polynomials
Dividing 6x3+8x2−11x+26x^3+8x^2-11x+2 by (3x−2)(3x-2) gives a quadratic quotient 2x2+bx+c2x^2+bx+c. State bb and cc as 'b, c'.

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Question 604

[2 marks]polynomials
Verifying (3x−2)(3x-2) is a factor: evaluate 6x3+8x2+26x^3+8x^2+2 at x=23x=\dfrac23 (ignoring the kxkx term for now), giving a fraction.

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Question 701

[1 marks]trigonometry, R-form
Expressing 3cos⁡x−5sin⁡x3\cos x-5\sin x in the form Rsin⁡(x+α)R\sin(x+\alpha) with R>0R>0 and 0°<α<360°0°<\alpha<360°, what are the values of RR and α\alpha (to 1 decimal place)?
  1. AR=34, α≈31.0°R=\sqrt{34},\ \alpha\approx31.0°
  2. BR=34, α≈239.0°R=\sqrt{34},\ \alpha\approx239.0°
  3. CR=8, α≈149.0°R=\sqrt8,\ \alpha\approx149.0°
  4. DR=34, α≈149.0°R=\sqrt{34},\ \alpha\approx149.0°

Question 702

[1 marks]trigonometry, R-form
Given that 3cos⁡x−5sin⁡x=34sin⁡(x+149.0°)3\cos x-5\sin x=\sqrt{34}\sin(x+149.0°), solve 3cos⁡x−5sin⁡x=23\cos x-5\sin x=2 for 0°<x<360°0°<x<360°, to the nearest 0.1°0.1°.
  1. Ax≈190.9°x\approx190.9° or 51.0°51.0°
  2. Bx≈10.9°x\approx10.9° or 231.0°231.0°
  3. Cx≈20.1°x\approx20.1° or 159.9°159.9°
  4. Dx≈128.9°x\approx128.9° or 349.1°349.1°

Question 703

[2 marks]trigonometry, R-form
Matching Rsin⁡(x+α)=Rsin⁡xcos⁡α+Rcos⁡xsin⁡αR\sin(x+\alpha)=R\sin x\cos\alpha+R\cos x\sin\alpha with 3cos⁡x−5sin⁡x3\cos x-5\sin x, state Rsin⁡αR\sin\alpha and Rcos⁡αR\cos\alpha as 'a, b'.

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Question 704

[2 marks]trigonometry, R-form
Using 34sin⁡(x+149.0°)=2\sqrt{34}\sin(x+149.0°)=2, evaluate 2/342/\sqrt{34}, correct to 4 decimal places.

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Question 801

[1 marks]parametric equations, coordinate geometry
Find, in the form y=mx+cy=mx+c, the equation of a line with gradient mm that passes through the point (m,m)(m,m).
  1. Ay=mx−m−m2y=mx-m-m^2
  2. By=mxy=mx
  3. Cy=mx+m2−my=mx+m^2-m
  4. Dy=mx+m−m2y=mx+m-m^2

Question 802

[1 marks]parametric equations, coordinate geometry
A curve is given parametrically by x=2+sin⁡θx=2+\sin\theta, y=6cos⁡θy=6\cos\theta. Find dydx\dfrac{dy}{dx} in terms of θ\theta.
  1. A6tan⁡θ6\tan\theta
  2. B−6cot⁡θ-6\cot\theta
  3. C−6tan⁡θ-6\tan\theta
  4. D−16tan⁡θ-\dfrac16\tan\theta

Question 803

[1 marks]parametric equations, coordinate geometry
A curve is given parametrically by x=2+sin⁡θx=2+\sin\theta, y=6cos⁡θy=6\cos\theta. Which of the following is the correct Cartesian equation relating xx and yy?
  1. Ay2−36x2+144x−108=0y^2-36x^2+144x-108=0
  2. By2+36x2−144x+108=0y^2+36x^2-144x+108=0
  3. Cy2+36x2−144x+144=0y^2+36x^2-144x+144=0
  4. Dy2+36x2−72x+108=0y^2+36x^2-72x+108=0

Question 804

[2 marks]parametric equations, coordinate geometry
For x=2+sin⁡θx=2+\sin\theta, y=6cos⁡θy=6\cos\theta, express sin⁡θ\sin\theta in terms of xx.

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Question 805

[2 marks]parametric equations, coordinate geometry
For x=2+sin⁡θx=2+\sin\theta, y=6cos⁡θy=6\cos\theta, express cos⁡θ\cos\theta in terms of yy.

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Question 806

[1 marks]parametric equations, coordinate geometry
Using sin⁡2θ+cos⁡2θ=1\sin^2\theta+\cos^2\theta=1 with sin⁡θ=x−2\sin\theta=x-2, cos⁡θ=y/6\cos\theta=y/6, state the equation before simplifying, in the form (x−2)2+y2/36=k(x-2)^2+y^2/36=k. State kk.

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Question 901

[1 marks]trigonometric equations
Solve ∣2sin⁡x−3∣=1|2\sin x-3|=1 for 0°≤x≤360°0°\leq x\leq360°.
  1. ANo solution
  2. Bx=90°x=90° only
  3. Cx=90°x=90° and x=270°x=270°
  4. Dx=30°x=30° and x=150°x=150°

Question 902

[1 marks]trigonometric equations
Solve 32sin⁡2θ=2sin⁡2θ\dfrac{3}{2}\sin2\theta=2\sin^2\theta for 0°≤θ≤360°0°\leq\theta\leq360°, to the nearest 0.1°0.1°.
  1. Aθ=0°,180°,360°\theta=0°,180°,360° only
  2. Bθ=0°,180°,360°,33.7°,213.7°\theta=0°,180°,360°,33.7°,213.7°
  3. Cθ=0°,180°,360°,56.3°,236.3°\theta=0°,180°,360°,56.3°,236.3°
  4. Dθ=56.3°,236.3°\theta=56.3°,236.3° only

Question 903

[2 marks]trigonometric equations
Solving ∣2sin⁡x−3∣=1|2\sin x-3|=1 splits into 2sin⁡x−3=12\sin x-3=1 (giving sin⁡x=2\sin x=2, no solution) and 2sin⁡x−3=−12\sin x-3=-1. State the value of sin⁡x\sin x from the second case.

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Question 904

[2 marks]trigonometric equations
Rewriting 32sin⁡2θ=2sin⁡2θ\dfrac32\sin2\theta=2\sin^2\theta using sin⁡2θ=2sin⁡θcos⁡θ\sin2\theta=2\sin\theta\cos\theta gives 3sin⁡θcos⁡θ=2sin⁡2θ3\sin\theta\cos\theta=2\sin^2\theta, i.e. sin⁡θ(3cos⁡θ−2sin⁡θ)=0\sin\theta(3\cos\theta-2\sin\theta)=0. From the second factor, state tan⁡θ\tan\theta as a fraction.

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Question 905

[2 marks]trigonometric equations
From the factor sin⁡θ=0\sin\theta=0 in sin⁡θ(3cos⁡θ−2sin⁡θ)=0\sin\theta(3\cos\theta-2\sin\theta)=0, state all solutions for 0°≤θ≤360°0°\leq\theta\leq360°, as 'a, b, c'.

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Question 1001

[1 marks]differentiation, rates of change
Given y=3x−6xy=\dfrac{3x-6}{x}, where xx and yy are functions of tt with dydt=0.6\dfrac{dy}{dt}=0.6, find dxdt\dfrac{dx}{dt} when y=1y=1.
  1. A0.2250.225
  2. B0.40.4
  3. C0.90.9
  4. D1.111.11

Question 1002

[1 marks]differentiation, rates of change
Given y=5−3xy=5-\dfrac{3}{x}, and that yy increases from 44 by a small amount p25\dfrac{p}{25}, find the approximate change in xx in terms of pp.
  1. A3p25\dfrac{3p}{25}
  2. Bp25\dfrac{p}{25}
  3. Cp75\dfrac{p}{75}
  4. D16p75\dfrac{16p}{75}

Question 1003

[1 marks]differentiation, rates of change
Given y=5−3xy=5-\dfrac{3}{x}, and that yy increases from 44 by a small amount p25\dfrac{p}{25}, giving an approximate change in xx of 3p25\dfrac{3p}{25} (at x=3x=3), find the corresponding percentage change in xx, in terms of pp.
  1. A4p%4p\%
  2. B4p3%\dfrac{4p}{3}\%
  3. C12p%12p\%
  4. D4p25%\dfrac{4p}{25}\%

Question 1004

[2 marks]differentiation, rates of change
For y=3x−6x=3−6xy=\dfrac{3x-6}{x}=3-\dfrac6x, find dydx\dfrac{dy}{dx} in terms of xx.

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Question 1005

[2 marks]differentiation, rates of change
When y=1y=1 in y=3−6xy=3-\dfrac6x, solve for xx.

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Question 1006

[2 marks]differentiation, rates of change
For y=5−3xy=5-\dfrac3x, find dydx\dfrac{dy}{dx} in terms of xx.

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Question 1101

[1 marks]vectors
Points A(1,6,2)A(1,6,2) and B(−1,11,−1)B(-1,11,-1) are given, along with a point C(−2,−5,11)C(-2,-5,11) and a point PP with position vector (2p+1, −5p+6, 3p+2)(2p+1,\,-5p+6,\,3p+2). Find CP→\overrightarrow{CP} in terms of pp.
  1. A(2p+3, −5p+1, 3p−9)(2p+3,\ -5p+1,\ 3p-9)
  2. B(2p−1, −5p+1, 3p+13)(2p-1,\ -5p+1,\ 3p+13)
  3. C(−2p−3, 5p−11, −3p+9)(-2p-3,\ 5p-11,\ -3p+9)
  4. D(2p+3, −5p+11, 3p−9)(2p+3,\ -5p+11,\ 3p-9)

Question 1102

[1 marks]vectors
Given AB→=(−2,5,−3)\overrightarrow{AB}=(-2,5,-3) and CP→=(2p+3, −5p+11, 3p−9)\overrightarrow{CP}=(2p+3,\,-5p+11,\,3p-9), find CP→⋅AB→\overrightarrow{CP}\cdot\overrightarrow{AB} in terms of pp.
  1. A−38p+22-38p+22
  2. B−38p+76-38p+76
  3. C−22p+76-22p+76
  4. D38p−7638p-76

Question 1103

[1 marks]vectors
Given that CP→⋅AB→=−38p+76\overrightarrow{CP}\cdot\overrightarrow{AB}=-38p+76 and that CPCP is perpendicular to ABAB, find the value of pp.
  1. A−2-2
  2. B00
  3. C0.50.5
  4. D22

Question 1104

[1 marks]vectors
Points A(1,6,2)A(1,6,2), B(−1,11,−1)B(-1,11,-1) and P=(2p+1,−5p+6,3p+2)P=(2p+1,-5p+6,3p+2) are collinear for all values of pp. Point CC has position vector (−2,−5,11)(-2,-5,11). Given that CP→\overrightarrow{CP} is perpendicular to AB→\overrightarrow{AB} when p=2p=2, find the shortest distance from CC to the line ABAB.
  1. A5959
  2. B58\sqrt{58}
  3. C38\sqrt{38}
  4. D59\sqrt{59}

Question 1105

[2 marks]vectors
State AB→=B−A\overrightarrow{AB}=B-A for A=(1,6,2)A=(1,6,2), B=(−1,11,−1)B=(-1,11,-1), as 'x,y,z'.

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Question 1106

[2 marks]vectors
State AP→=P−A\overrightarrow{AP}=P-A in terms of pp, for P=(2p+1,−5p+6,3p+2)P=(2p+1,-5p+6,3p+2), A=(1,6,2)A=(1,6,2), as 'x,y,z'.

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Question 1107

[2 marks]vectors
Given AP→=p(2,−5,3)\overrightarrow{AP}=p(2,-5,3) and AB→=(−2,5,−3)\overrightarrow{AB}=(-2,5,-3), state the scalar mm such that AB→=m(2,−5,3)\overrightarrow{AB}=m(2,-5,3) (used to confirm AA, BB, PP are collinear).

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Question 1201

[1 marks]calculus, integration
Given that ddx(x4−x2)=4(4−x2)3/2\dfrac{d}{dx}\left(\dfrac{x}{\sqrt{4-x^2}}\right)=\dfrac{4}{(4-x^2)^{3/2}}, evaluate ∫018(4−x2)3/2 dx\displaystyle\int_0^1\dfrac{8}{(4-x^2)^{3/2}}\,dx.
  1. A233\dfrac{2\sqrt3}{3}
  2. B433\dfrac{4\sqrt3}{3}
  3. C23\dfrac23
  4. D33\dfrac{\sqrt3}{3}

Question 1202

[1 marks]calculus, integration
The region enclosed by y=x4−x2y=\dfrac{x}{\sqrt{4-x^2}}, the xx-axis, and the lines x=−1x=-1 and x=1x=1 is rotated about the xx-axis through 360°360°. Which of the following gives the volume generated?
  1. A2π(ln⁡3−1)2\pi(\ln3-1)
  2. B2π(1−ln⁡3)2\pi(1-\ln3)
  3. Cπ(ln⁡3−1)\pi(\ln3-1)
  4. D2π(ln⁡3+1)2\pi(\ln3+1)

Question 1203

[2 marks]calculus, integration
Differentiating x4−x2=x(4−x2)−1/2\dfrac{x}{\sqrt{4-x^2}}=x(4-x^2)^{-1/2} by the product rule needs ddx(4−x2)−1/2\dfrac{d}{dx}(4-x^2)^{-1/2}. State this derivative, in terms of xx.

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Question 1204

[2 marks]calculus, integration
Evaluate 14−12=13\dfrac{1}{\sqrt{4-1^2}}=\dfrac1{\sqrt3} as a decimal, correct to 3 decimal places (used in [x4−x2]01\left[\dfrac{x}{\sqrt{4-x^2}}\right]_0^1).

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Question 1205

[2 marks]calculus, integration
The integrand x24−x2\dfrac{x^2}{4-x^2} can be rewritten as −1+44−x2-1+\dfrac4{4-x^2}. Confirm by expanding −1+44−x2-1+\dfrac4{4-x^2} over the common denominator 4−x24-x^2: state the resulting numerator (it should equal x2x^2).

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Question 1206

[2 marks]calculus, integration
Evaluate [−x]01[-x]_0^1 (one part of [−x+ln⁡2+x2−x]01\left[-x+\ln\dfrac{2+x}{2-x}\right]_0^1 used in the volume integral).

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Question 1301

[1 marks]completing the square, Newton-Raphson
Expressing 12x−3x2+1512x-3x^2+15 in the form a+b(x+c)2a+b(x+c)^2 gives 27−3(x−2)227-3(x-2)^2. What are the coordinates of the turning point of y=12x−3x2+15y=12x-3x^2+15, and is it a maximum or minimum?
  1. A(2,27)(2,27), minimum
  2. B(−2,27)(-2,27), maximum
  3. C(2,−27)(2,-27), maximum
  4. D(2,27)(2,27), maximum

Question 1302

[1 marks]completing the square, Newton-Raphson
The graphs of y=e−xy=e^{-x} and y=12x−3x2+15y=12x-3x^2+15 are sketched on the same axes. How many real roots does the equation e−x+3x2−12x−15=0e^{-x}+3x^2-12x-15=0 have?
  1. A00
  2. B11
  3. C22
  4. D33

Question 1303

[1 marks]completing the square, Newton-Raphson
Using x1=−0.8x_1=-0.8 and the Newton-Raphson formula xn+1=xn−f(xn)f′(xn)x_{n+1}=x_n-\dfrac{f(x_n)}{f'(x_n)}, where f(x)=e−x+3x2−12x−15f(x)=e^{-x}+3x^2-12x-15, find the root of f(x)=0f(x)=0 correct to 4 decimal places.
  1. A−0.9000-0.9000
  2. B−0.8650-0.8650
  3. C−0.8000-0.8000
  4. D−0.7900-0.7900

Question 1304

[2 marks]completing the square, Newton-Raphson
Complete the square: write 12x−3x2+1512x-3x^2+15 as −3(x−2)2+d-3(x-2)^2+d for some constant dd. State dd.

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Question 1305

[2 marks]completing the square, Newton-Raphson
For f(x)=e−x+3x2−12x−15f(x)=e^{-x}+3x^2-12x-15, state f′(x)f'(x) in terms of xx.

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Question 1306

[2 marks]completing the square, Newton-Raphson
Using x1=−0.8x_1=-0.8, evaluate f(−0.8)f(-0.8) for f(x)=e−x+3x2−12x−15f(x)=e^{-x}+3x^2-12x-15, correct to 4 decimal places.

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Question 1307

[2 marks]completing the square, Newton-Raphson
Evaluate f′(−0.8)f'(-0.8) for f′(x)=−e−x+6x−12f'(x)=-e^{-x}+6x-12, correct to 4 decimal places.

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Question 1401

[1 marks]arithmetic and geometric progressions
In an arithmetic progression, the 6th term is half the 4th term, and the 3rd term is 15. Find the first term aa and common difference dd.
  1. Aa=21, d=3a=21,\ d=3
  2. Ba=−15, d=15a=-15,\ d=15
  3. Ca=21, d=−3a=21,\ d=-3
  4. Da=15, d=0a=15,\ d=0

Question 1402

[1 marks]arithmetic and geometric progressions
For the arithmetic progression with first term a=21a=21 and common difference d=−3d=-3, find the least number of terms nn for which the sum SnS_n becomes, and remains, less than 6565.
  1. An=3n=3
  2. Bn=4n=4
  3. Cn=12n=12
  4. Dn=11n=11

Question 1403

[1 marks]arithmetic and geometric progressions
Evaluate ∑r=1103(34)r\displaystyle\sum_{r=1}^{10}3\left(\dfrac34\right)^r, correct to 4 significant figures.
  1. A2.2502.250
  2. B8.4938.493
  3. C9.0009.000
  4. D11.4911.49

Question 1404

[2 marks]arithmetic and geometric progressions
In the AP, T3=a+2d=15T_3=a+2d=15 and T6=12T4T_6=\frac12T_4 gives a+7d=0a+7d=0, so a=−7da=-7d. Substituting into a+2d=15a+2d=15 gives an equation in dd, in the form md=15md=15. State mm.

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Question 1405

[2 marks]arithmetic and geometric progressions
Using Sn=3n(15−n)2S_n=\dfrac{3n(15-n)}2 (for the AP with a=21a=21, d=−3d=-3), evaluate S10S_{10}.

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Question 1406

[2 marks]arithmetic and geometric progressions
Using Sn=3n(15−n)2S_n=\dfrac{3n(15-n)}2, evaluate S11S_{11}.

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Question 1407

[2 marks]arithmetic and geometric progressions
For ∑r=1103(34)r\sum_{r=1}^{10}3\left(\frac34\right)^r, the series has first term 3×343\times\frac34. State this first term as a decimal.

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Question 1501

[1 marks]calculus, partial fractions
The radius of a circle depends on time according to r=t3+1r=t^3+1, and its area is A=πr2A=\pi r^2. Find dAdt\dfrac{dA}{dt} at t=2t=2, in terms of π\pi.
  1. A108π108\pi
  2. B192π192\pi
  3. C72π72\pi
  4. D216π216\pi

Question 1502

[1 marks]calculus, partial fractions
The curve y=x2ln⁡xy=x^2\ln x has dydx=x(2ln⁡x+1)\dfrac{dy}{dx}=x(2\ln x+1), which is zero at x=e−1/2x=e^{-1/2}, giving the point (e−1/2, −12e−1)\left(e^{-1/2},\,-\tfrac12e^{-1}\right). Using d2ydx2=2ln⁡x+3\dfrac{d^2y}{dx^2}=2\ln x+3, determine the nature of this turning point.
  1. AMaximum, since d2ydx2=2>0\dfrac{d^2y}{dx^2}=2>0 at that point
  2. BPoint of inflection, since d2ydx2=0\dfrac{d^2y}{dx^2}=0 at that point
  3. CMinimum, since d2ydx2=2>0\dfrac{d^2y}{dx^2}=2>0 at that point
  4. DMaximum, since d2ydx2=−1<0\dfrac{d^2y}{dx^2}=-1<0 at that point

Question 1503

[1 marks]calculus, partial fractions
Express 6x2+7x−2(x−1)(x−2)(x+2)\dfrac{6x^2+7x-2}{(x-1)(x-2)(x+2)} in partial fractions.
  1. A−11/3x−1+9x−2−2/3x+2\dfrac{-11/3}{x-1}+\dfrac{9}{x-2}-\dfrac{2/3}{x+2}
  2. B−11/3x−1+9x−2+2/3x+2\dfrac{-11/3}{x-1}+\dfrac{9}{x-2}+\dfrac{2/3}{x+2}
  3. C11/3x−1+9x−2+2/3x+2\dfrac{11/3}{x-1}+\dfrac{9}{x-2}+\dfrac{2/3}{x+2}
  4. D−11/3x−1+2/3x−2+9x+2\dfrac{-11/3}{x-1}+\dfrac{2/3}{x-2}+\dfrac{9}{x+2}

Question 1504

[2 marks]calculus, partial fractions
For r=t3+1r=t^3+1 and A=πr2A=\pi r^2, state dAdt\dfrac{dA}{dt} in terms of tt (general expression, before substituting t=2t=2).

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Question 1505

[2 marks]calculus, partial fractions
For y=x2ln⁡xy=x^2\ln x, find dydx\dfrac{dy}{dx} in terms of xx.

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Question 1506

[2 marks]calculus, partial fractions
Setting dydx=x(2ln⁡x+1)=0\dfrac{dy}{dx}=x(2\ln x+1)=0 for x>0x>0, the turning point requires 2ln⁡x+1=02\ln x+1=0. State ln⁡x\ln x at the turning point.

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Question 1507

[2 marks]calculus, partial fractions
For y=x2ln⁡xy=x^2\ln x, state d2ydx2\dfrac{d^2y}{dx^2} in terms of xx.

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Question 1508

[2 marks]calculus, partial fractions
For 6x2+7x−2(x−1)(x−2)(x+2)=Ax−1+Bx−2+Cx+2\dfrac{6x^2+7x-2}{(x-1)(x-2)(x+2)}=\dfrac A{x-1}+\dfrac B{x-2}+\dfrac C{x+2}, substituting x=2x=2 gives 36=B(1)(4)36=B(1)(4). State BB.

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Question 1509

[2 marks]calculus, partial fractions
Verifying the partial fractions A=−113A=-\frac{11}3, B=9B=9, C=23C=\frac23: evaluate 6x2+7x−26x^2+7x-2 at x=0x=0 (this should match −4A−2B+2C-4A-2B+2C from the identity).

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