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ZIMSEC A Level · 6042/2 · N2023

Pure Mathematics Paper 2 November 2023

Questions
49
Total marks
152
Syllabus code
6042/2

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Questions
49
Pass mark
30
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Answer every question in the printed order, get marked at the end, then see the answers.

The questions

Question 101

[3 marks]Indices and logarithms
Simplify 32x−3⋅81x+1227x\dfrac{3^{2x-3}\cdot81^{x+\frac12}}{27^x}, giving the answer as a single power of 3.

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Question 102

[3 marks]Indices and logarithms
Solve 33x−1=15x−13^{3x-1}=\dfrac{1}{5^{x-1}}, giving the answer in exact form.

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Question 201

[2 marks]Polynomials: factor theorem and completing the square
Given the polynomial Q(x)=2x3+3x2−4x−1Q(x)=2x^3+3x^2-4x-1, evaluate Q(1)Q(1).

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Question 202

[3 marks]Polynomials: factor theorem and completing the square
Given Q(x)=2x3+3x2−4x−1Q(x)=2x^3+3x^2-4x-1 and that x=1x=1 is a root, find the polynomial P(x)P(x) such that Q(x)=(x−1)P(x)Q(x)=(x-1)P(x).

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Question 203

[3 marks]Polynomials: factor theorem and completing the square
Express P(x)=2x2+5x+1P(x)=2x^2+5x+1 in the form A(x+B)2+CA(x+B)^2+C.

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Question 204

[1 marks]Polynomials: factor theorem and completing the square
Given that P(x)=2(x+54)2−178P(x)=2\left(x+\dfrac54\right)^2-\dfrac{17}{8}, state the minimum value of P(x)P(x).

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Question 301

[3 marks]Joint variation
The curved surface area AA of a cylindrical drum varies jointly as its base diameter dd and its height ll, so A=kdlA=kdl. Given A=2.64 m2A=2.64\,\text{m}^2 when the base radius is 0.350.35 m and the height is 1.21.2 m, find kk.

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Question 302

[2 marks]Joint variation
In A=kdlA=kdl for the curved surface area of a cylindrical drum, the drum is described by its base radius of 0.350.35 m. Why is 0.700.70 and not 0.350.35 substituted for dd?
  1. ABecause dd in the formula stands for the diameter, which is twice the radius the question quotes.
  2. BBecause the surface area must always be doubled when a cylinder is closed at both of its ends.
  3. CBecause the height of 1.21.2 m has to be halved first, and the radius is doubled to compensate for it.
  4. DBecause a curved surface area is measured in square metres, so every length in it is used twice over.

Question 303

[3 marks]Joint variation
Using A=227dlA=\dfrac{22}{7}dl for the curved surface area of a cylindrical drum, calculate the radius, in metres to 2 decimal places, of a cylinder whose curved surface area is 14.52 m214.52\,\text{m}^2 and whose height is 33 m.

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Question 401

[2 marks]Quadratic equations and the discriminant
Given f(x)=kx2+3x+3f(x)=kx^2+3x+3 and g(x)=kx+7g(x)=kx+7, write the equation f(x)=g(x)f(x)=g(x) as a quadratic equation equal to zero.

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Question 402

[3 marks]Quadratic equations and the discriminant
Find the range of values of kk for which kx2+(3−k)x−4=0kx^2+(3-k)x-4=0 has two distinct real solutions.

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Question 501

[3 marks]Identities and partial fractions
Given that 2x3+ax2+x−3≡(bx2+c)(x−3)2x^3+ax^2+x-3\equiv(bx^2+c)(x-3), find the constants aa, bb and cc.

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Question 502

[2 marks]Identities and partial fractions
Which is the correct way to set up 1+6x(2x2+1)(x−3)\dfrac{1+6x}{(2x^2+1)(x-3)} in partial fractions?
  1. AA2x2+1+Bx+Cx−3\dfrac{A}{2x^2+1}+\dfrac{Bx+C}{x-3}, since the larger of the two denominators always takes the constant numerator.
  2. BAx+B2x2+1+Cx+Dx−3\dfrac{Ax+B}{2x^2+1}+\dfrac{Cx+D}{x-3}, since the numerator of the original fraction is itself linear in xx.
  3. CA2x2+1+Bx−3\dfrac{A}{2x^2+1}+\dfrac{B}{x-3}, since one unknown constant belongs above each of the two factors of the denominator, whatever the degree of that factor happens to be.
  4. DAx+B2x2+1+Cx−3\dfrac{Ax+B}{2x^2+1}+\dfrac{C}{x-3}, since an irreducible quadratic factor takes a linear numerator and a linear factor takes a constant.

Question 503

[3 marks]Identities and partial fractions
Express 1+6x(2x2+1)(x−3)\dfrac{1+6x}{(2x^2+1)(x-3)} in partial fractions.

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Question 601

[1 marks]Composite functions, area by integration and the trapezium rule
Given t(x)=ext(x)=e^x and h(x)=2x+3h(x)=2x+3, find th(x)th(x).

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Question 602

[3 marks]Composite functions, area by integration and the trapezium rule
Find, by integration, the exact area between y=12x+20y=12x+20, y=e2x+3y=e^{2x+3} and the lines x=−1.5x=-1.5 and x=0x=0.

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Question 603

[2 marks]Composite functions, area by integration and the trapezium rule
The trapezium rule is applied to ∫−1.50(12x+20−e2x+3)dx\displaystyle\int_{-1.5}^{0}\left(12x+20-e^{2x+3}\right)dx with 4 ordinates. State the strip width hh.

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Question 604

[3 marks]Composite functions, area by integration and the trapezium rule
Estimate ∫−1.50(12x+20−e2x+3)dx\displaystyle\int_{-1.5}^{0}\left(12x+20-e^{2x+3}\right)dx using the trapezium rule with 4 ordinates and strip width 0.50.5, giving the answer to 2 significant figures.

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Question 605

[3 marks]Composite functions, area by integration and the trapezium rule
The exact area of a region is 6.95726.9572 square units and the trapezium rule estimates it as 6.17496.1749. Calculate the relative error, to 2 significant figures.

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Question 606

[2 marks]Composite functions, area by integration and the trapezium rule
The trapezium rule applied to y=12x+20−e2x+3y=12x+20-e^{2x+3} between x=−1.5x=-1.5 and x=0x=0 gives 6.176.17, while the exact value is 6.966.96. Why does the rule fall short here?
  1. ABecause four ordinates is an even number, and the trapezium rule can only be exact when the count of ordinates used is an odd one instead.
  2. BBecause the curve is concave down over the interval, so each straight chord lies below the curve and every strip is undercounted.
  3. CBecause the interval −1.5-1.5 to 00 is negative in width, which subtracts a fixed amount from the total the rule returns.
  4. DBecause the rule always loses accuracy whenever an exponential term appears anywhere in the integrand being used.

Question 701

[3 marks]Trigonometric identities and equations
In proving 2cot⁡2θ1−tan⁡2θ≡cot⁡θ\dfrac{2\cot2\theta}{1-\tan^2\theta}\equiv\cot\theta, the denominator 1−tan⁡2θ1-\tan^2\theta is first written as a single fraction. Which fraction is it?
  1. A1cos⁡2θ\dfrac{1}{\cos^2\theta}, because 1−tan⁡2θ1-\tan^2\theta is one of the standard Pythagorean identities of trigonometry.
  2. Bsin⁡2θ−cos⁡2θcos⁡2θ\dfrac{\sin^2\theta-\cos^2\theta}{\cos^2\theta}, because subtracting a squared tangent reverses the order of the two terms, leaving the sine squared written in front of the cosine squared.
  3. Ccos⁡2θ−sin⁡2θcos⁡2θ\dfrac{\cos^2\theta-\sin^2\theta}{\cos^2\theta}, because tan⁡2θ=sin⁡2θcos⁡2θ\tan^2\theta=\dfrac{\sin^2\theta}{\cos^2\theta} and the two terms go over the common denominator cos⁡2θ\cos^2\theta.
  4. Dcos⁡2θ−sin⁡2θsin⁡2θ\dfrac{\cos^2\theta-\sin^2\theta}{\sin^2\theta}, because the tangent is defined as sine over cosine in that particular order.

Question 702

[3 marks]Trigonometric identities and equations
Write 2csc⁡2θ−12\csc^2\theta-1 in terms of cot⁡θ\cot\theta only.

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Question 703

[3 marks]Trigonometric identities and equations
For the quadratic 2cot⁡2θ−cot⁡θ+1=02\cot^2\theta-\cot\theta+1=0, treated as a quadratic in cot⁡θ\cot\theta, calculate the discriminant b2−4acb^2-4ac.

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Question 704

[3 marks]Trigonometric identities and equations
The equation 2cot⁡2θ1−tan⁡2θ=2csc⁡2θ−1\dfrac{2\cot2\theta}{1-\tan^2\theta}=2\csc^2\theta-1 reduces to 2cot⁡2θ−cot⁡θ+1=02\cot^2\theta-\cot\theta+1=0, whose discriminant is −7-7. What does that tell you about the solutions for 0∘≤θ≤360∘0^\circ\le\theta\le360^\circ?
  1. AThere is one solution, because a negative discriminant leaves only the single repeated root at the vertex.
  2. BThere are no solutions, because a negative discriminant means cot⁡θ\cot\theta can take no real value at all.
  3. CThere are exactly two solutions, because every quadratic equation still has two roots when they are counted properly.
  4. DThere are four solutions, because each value of cot⁡θ\cot\theta produces two angles within a full turn of 360∘360^\circ.

Question 705

[2 marks]Trigonometric identities and equations
State the number of solutions of 2cot⁡2θ1−tan⁡2θ=2csc⁡2θ−1\dfrac{2\cot2\theta}{1-\tan^2\theta}=2\csc^2\theta-1 in the range 0∘≤θ≤360∘0^\circ\le\theta\le360^\circ.

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Question 801

[3 marks]Determinants and inverse matrices
Expand the determinant of A=(121x1x+12x−20)A=\begin{pmatrix}1&2&1\\x&1&x+1\\2&x-2&0\end{pmatrix} and give it as a simplified expression in xx.

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Question 802

[2 marks]Determinants and inverse matrices
The determinant of A=(121x1x+12x−20)A=\begin{pmatrix}1&2&1\\x&1&x+1\\2&x-2&0\end{pmatrix} simplifies to 3x+43x+4. Given that the determinant equals 13 and x>0x>0, find xx.

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Question 803

[3 marks]Determinants and inverse matrices
For A=(121314210)A=\begin{pmatrix}1&2&1\\3&1&4\\2&1&0\end{pmatrix}, find the cofactor of the entry in row 1, column 1.

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Question 804

[3 marks]Determinants and inverse matrices
The inverse of A=(121314210)A=\begin{pmatrix}1&2&1\\3&1&4\\2&1&0\end{pmatrix} can be written as 113\dfrac{1}{13} times a matrix. Give the first row of that matrix.

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Question 805

[3 marks]Determinants and inverse matrices
For two invertible matrices AA and BB, which expression equals (AB)−1(AB)^{-1}?
  1. A1AB\dfrac{1}{AB}, because the inverse of any product is simply one divided by the whole of the product itself.
  2. B(BA)−1(BA)^{-1}, because a product of two matrices gives the same result whichever way round the two are written.
  3. CA−1B−1A^{-1}B^{-1}, because taking an inverse acts on each of the two factors separately and leaves the order of the product exactly as it was written.
  4. DB−1A−1B^{-1}A^{-1}, because undoing a product means undoing the last operation first, which reverses the order of the factors.

Question 806

[2 marks]Determinants and inverse matrices
(AB)−1=B−1A−1(AB)^{-1}=B^{-1}A^{-1} works out to 1104\dfrac{1}{104} times the matrix (−1163???−110−8)\begin{pmatrix}-11&6&3\\?&?&?\\-1&10&-8\end{pmatrix} for B−1=18(1−11210103)B^{-1}=\dfrac18\begin{pmatrix}1&-1&1\\2&1&0\\1&0&3\end{pmatrix} and A−1=113(−4178−2−113−5)A^{-1}=\dfrac{1}{13}\begin{pmatrix}-4&1&7\\8&-2&-1\\1&3&-5\end{pmatrix}. Give the missing middle row.

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Question 901

[2 marks]Sequences and series: sums, general term and inequalities
The sum of nn terms of a sequence is Sn=n4(5−n)S_n=\dfrac{n}{4}(5-n). Find S2S_2.

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Question 902

[2 marks]Sequences and series: sums, general term and inequalities
The sum of nn terms of a sequence is Sn=n4(5−n)S_n=\dfrac{n}{4}(5-n). Find the third term of the sequence.

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Question 903

[3 marks]Sequences and series: sums, general term and inequalities
A sequence has first three terms 11, 0.50.5 and 00. Find its general term TnT_n in terms of nn.

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Question 904

[3 marks]Sequences and series: sums, general term and inequalities
The sum of nn terms of a sequence is Sn=n4(5−n)S_n=\dfrac{n}{4}(5-n). Calculate the number of terms needed for the sum to equal −9-9.

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Question 905

[3 marks]Sequences and series: sums, general term and inequalities
Solving n4(5−n)=−9\dfrac{n}{4}(5-n)=-9 for the number of terms gives n=9n=9 and n=−4n=-4. Why is n=−4n=-4 discarded?
  1. ABecause the formula Sn=n4(5−n)S_n=\dfrac{n}{4}(5-n) was only stated by the question for values of nn larger than 5.
  2. BBecause a negative root of any quadratic equation is always an extraneous solution introduced by the squaring step.
  3. CBecause nn counts how many terms have been added, so it can only be a positive whole number.
  4. DBecause the sum −9-9 is itself negative, and two negative quantities cannot appear on opposite sides of one equation.

Question 906

[3 marks]Sequences and series: sums, general term and inequalities
The sum of nn terms of a sequence is Sn=n4(5−n)S_n=\dfrac{n}{4}(5-n). Find the range of values of nn for which Sn>0S_n>0.

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Question 1001

[2 marks]Coordinate geometry: lines, circles and tangents
A quadrilateral has vertices A(−1;1)A(-1;1) and B(3;7)B(3;7). Find the gradient of line ABAB.

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Question 1002

[2 marks]Coordinate geometry: lines, circles and tangents
Find the equation of the line through A(−1;1)A(-1;1) and B(3;7)B(3;7).

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Question 1003

[2 marks]Coordinate geometry: lines, circles and tangents
A quadrilateral has vertices A(−1;1)A(-1;1) and D(2;−1)D(2;-1). Find the gradient of line ADAD.

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Question 1004

[3 marks]Coordinate geometry: lines, circles and tangents
Points C(4;2)C(4;2) and D(2;−1)D(2;-1) are two vertices of a quadrilateral. Find the exact length CDCD.

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Question 1005

[3 marks]Coordinate geometry: lines, circles and tangents
Find the equation of the circle with centre D(2;−1)D(2;-1) and radius 13\sqrt{13} in the form x2+y2+ax+by=cx^2+y^2+ax+by=c, stating aa, bb and cc.

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Question 1006

[3 marks]Coordinate geometry: lines, circles and tangents
The circle x2+y2−4x+2y=8x^2+y^2-4x+2y=8 has centre D(2;−1)D(2;-1) and passes through A(−1;1)A(-1;1), and line ABAB is perpendicular to line ADAD. Why does that make ABAB a tangent to the circle?
  1. ABecause DADA is a radius and ABAB is perpendicular to it at AA, the point where that radius meets the circle.
  2. BBecause the gradients of ABAB and ADAD multiply to give −1-1, and a product of −1-1 always signals a tangent.
  3. CBecause ABAB meets the circle at exactly one point, which is the very definition of a tangent to a curve.
  4. DBecause B(3;7)B(3;7) lies outside the circle, and any line drawn from a point outside a circle must touch it once.

Question 1201

[2 marks]Rational functions, graph transformations and inverse functions
Express g(x)=4x+52(x+1)g(x)=\dfrac{4x+5}{2(x+1)} in the form A+B2(x+1)A+\dfrac{B}{2(x+1)}, stating AA and BB.

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Question 1202

[3 marks]Rational functions, graph transformations and inverse functions
Which single transformation maps the graph of y=1xy=\dfrac1x onto the graph of y=1x+1y=\dfrac{1}{x+1}?
  1. AA translation of 1 unit in the positive xx direction, moving the vertical asymptote across to x=1x=1.
  2. BA reflection in the yy-axis, which turns the right-hand branch of the curve into the left-hand branch.
  3. CA translation of 1 unit in the negative xx direction, moving the vertical asymptote across to x=−1x=-1.
  4. DA stretch parallel to the xx-axis with factor 11, leaving both of the asymptotes exactly where they were.

Question 1203

[3 marks]Rational functions, graph transformations and inverse functions
Which single transformation maps the graph of y=1x+1y=\dfrac{1}{x+1} onto the graph of y=12(x+1)y=\dfrac{1}{2(x+1)}?
  1. AA reflection in the line y=xy=x, which exchanges the roles played by the horizontal and vertical asymptotes.
  2. BA stretch parallel to the yy-axis with factor 12\dfrac12, halving every yy-coordinate while the asymptotes stay put.
  3. CA stretch parallel to the xx-axis with factor 12\dfrac12, halving every xx-coordinate and carrying the vertical asymptote along with them.
  4. DA translation of 12\dfrac12 unit in the negative yy direction, dropping the whole curve down the page a little.

Question 1204

[2 marks]Rational functions, graph transformations and inverse functions
State the equations of the two asymptotes of y=2+12(x+1)y=2+\dfrac{1}{2(x+1)}.

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Question 1205

[3 marks]Rational functions, graph transformations and inverse functions
Find the inverse of g(x)=4x+52x+2g(x)=\dfrac{4x+5}{2x+2}.

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Question 1206

[3 marks]Rational functions, graph transformations and inverse functions
State the domain of g−1(x)=5−2x2x−4g^{-1}(x)=\dfrac{5-2x}{2x-4}, the inverse of g(x)=4x+52x+2g(x)=\dfrac{4x+5}{2x+2}.

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