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O Level Additional Mathematics Calculus Quiz

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O Level Additional Mathematics From Real Exams Generated by DeepSeek V4 Pro Updated 2026-06-03

Questions

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O-Level Additional Mathematics Quiz - Calculus

Name: _________________________ Class: _________________________ Date: _________________________ Score: ______ / 50

Duration: 1 hour 15 minutes Total Marks: 50

Instructions:

  • Answer ALL questions.
  • Show all working clearly. Marks are awarded for method.
  • Give non-exact answers to 3 significant figures, or 1 decimal place for angles in degrees.
  • You may use an approved calculator.
  • The number of marks is given in brackets [ ] at the end of each question or part question.

Section A: Differentiation Techniques (Questions 1–6)

Answer ALL questions in this section.

1. Differentiate with respect to xx: (a) y=3x42x3+5x7y = 3x^4 - 2x^3 + 5x - 7 [2] (b) y=2x3+xy = \frac{2}{x^3} + \sqrt{x} [2]

2. Find dydx\frac{dy}{dx} for each of the following: (a) y=(2x+1)(x23)y = (2x + 1)(x^2 - 3) [3] (b) y=x2+1x2y = \frac{x^2 + 1}{x - 2} [3]

3. Differentiate with respect to xx: (a) y=sin3xy = \sin 3x [2] (b) y=e2x+1y = e^{2x+1} [2] (c) y=ln(5x2)y = \ln(5x - 2) [2]

4. Given y=cos2xy = \cos^2 x, find dydx\frac{dy}{dx}. [3]

5. Find d2ydx2\frac{d^2y}{dx^2} when y=x36x2+9x+4y = x^3 - 6x^2 + 9x + 4. [3]

6. The curve CC has equation y=x33x2+2y = x^3 - 3x^2 + 2. (a) Find dydx\frac{dy}{dx}. [1] (b) Find the equation of the tangent to CC at the point where x=1x = 1. [3]


Section B: Applications of Differentiation (Questions 7–13)

Answer ALL questions in this section.

7. Find the coordinates of the stationary points on the curve y=2x33x212x+7y = 2x^3 - 3x^2 - 12x + 7 and determine the nature of each stationary point. [6]

8. The curve y=x2+16xy = x^2 + \frac{16}{x} is defined for x>0x > 0. (a) Find dydx\frac{dy}{dx}. [2] (b) Find the coordinates of the stationary point on the curve. [3] (c) Determine whether this stationary point is a maximum or a minimum. [2]

9. A curve has equation y=2x+1x1y = \frac{2x + 1}{x - 1}, where x1x \neq 1. (a) Find dydx\frac{dy}{dx}. [2] (b) Explain why the curve has no stationary points. [2]

10. The displacement ss metres of a particle from a fixed point OO at time tt seconds is given by s=t36t2+9ts = t^3 - 6t^2 + 9t, for t0t \geq 0. (a) Find the velocity of the particle when t=2t = 2. [2] (b) Find the acceleration of the particle when t=4t = 4. [2] (c) Find the times when the particle is instantaneously at rest. [2]

11. A rectangular box with a square base and an open top is to have a volume of 500 cm³. The base has side length xx cm and the height is hh cm. (a) Show that the external surface area AA cm² is given by A=x2+2000xA = x^2 + \frac{2000}{x}. [2] (b) Find the value of xx that minimises the surface area. [3] (c) Find the minimum surface area. [1]

12. The curve y=x3+ax2+bx+cy = x^3 + ax^2 + bx + c has a stationary point at (2,5)(2, 5) and passes through the point (1,3)(1, 3). Find the values of aa, bb, and cc. [5]

13. A spherical balloon is being inflated such that its volume VV cm³ increases at a constant rate of 100100 cm³/s. The volume of a sphere is V=43πr3V = \frac{4}{3}\pi r^3, where rr cm is the radius. (a) Find dVdr\frac{dV}{dr}. [1] (b) Find the rate at which the radius is increasing when r=5r = 5 cm. [3]


Section C: Integration (Questions 14–20)

Answer ALL questions in this section.

14. Find the following indefinite integrals: (a) (4x36x2+2x1)dx\int (4x^3 - 6x^2 + 2x - 1) \, dx [2] (b) (3x2+x3)dx\int \left( \frac{3}{x^2} + \sqrt[3]{x} \right) dx [2]

15. Integrate with respect to xx: (a) sin2xdx\int \sin 2x \, dx [2] (b) e3x1dx\int e^{3x-1} \, dx [2] (c) 12x+5dx\int \frac{1}{2x + 5} \, dx [2]

16. Evaluate: (a) 13(2x2x+1)dx\int_1^3 (2x^2 - x + 1) \, dx [3] (b) 0π4cos2xdx\int_0^{\frac{\pi}{4}} \cos 2x \, dx [3]

17. The curve y=f(x)y = f(x) passes through the point (2,10)(2, 10) and f(x)=3x24x+1f'(x) = 3x^2 - 4x + 1. Find f(x)f(x). [4]

18. Find the area of the region bounded by the curve y=x24x+3y = x^2 - 4x + 3, the xx-axis, and the lines x=0x = 0 and x=2x = 2. [5]

19. The diagram shows part of the curve y=4xx2y = 4x - x^2.

*(In the diagram, the curve intersects the $x$-axis at the origin and at $x = 4$.)*

Find the area of the shaded region bounded by the curve and the $x$-axis. [4]

20. A particle moves along a straight line. Its velocity vv m/s at time tt seconds is given by v=6tt2v = 6t - t^2, for 0t80 \leq t \leq 8. (a) Find the displacement of the particle from its starting point when t=4t = 4. [3] (b) Find the total distance travelled by the particle in the first 6 seconds. [4]


END OF QUIZ

Answers

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O-Level Additional Mathematics Quiz - Calculus: ANSWER KEY

Total Marks: 50


Section A: Differentiation Techniques (Questions 1–6)

1. (a) y=3x42x3+5x7y = 3x^4 - 2x^3 + 5x - 7 dydx=12x36x2+5\frac{dy}{dx} = 12x^3 - 6x^2 + 5 [M1] for differentiating each term correctly; [A1] for fully correct answer. [2]

(b) y=2x3+x1/2y = 2x^{-3} + x^{1/2} dydx=6x4+12x1/2=6x4+12x\frac{dy}{dx} = -6x^{-4} + \frac{1}{2}x^{-1/2} = -\frac{6}{x^4} + \frac{1}{2\sqrt{x}} [M1] for rewriting in index form and differentiating; [A1] for correct simplified answer. [2]


2. (a) y=(2x+1)(x23)y = (2x + 1)(x^2 - 3) Method 1 (Product Rule): u=2x+1u = 2x + 1, v=x23v = x^2 - 3 u=2u' = 2, v=2xv' = 2x dydx=uv+uv=2(x23)+(2x+1)(2x)\frac{dy}{dx} = u'v + uv' = 2(x^2 - 3) + (2x + 1)(2x) =2x26+4x2+2x=6x2+2x6= 2x^2 - 6 + 4x^2 + 2x = 6x^2 + 2x - 6

Method 2 (Expand first): y=2x3+x26x3y = 2x^3 + x^2 - 6x - 3 dydx=6x2+2x6\frac{dy}{dx} = 6x^2 + 2x - 6 [M1] for using product rule or expanding; [M1] for correct differentiation; [A1] for correct simplified answer. [3]

(b) y=x2+1x2y = \frac{x^2 + 1}{x - 2} Quotient Rule: u=x2+1u = x^2 + 1, v=x2v = x - 2 u=2xu' = 2x, v=1v' = 1 dydx=uvuvv2=2x(x2)(x2+1)(1)(x2)2\frac{dy}{dx} = \frac{u'v - uv'}{v^2} = \frac{2x(x - 2) - (x^2 + 1)(1)}{(x - 2)^2} =2x24xx21(x2)2=x24x1(x2)2= \frac{2x^2 - 4x - x^2 - 1}{(x - 2)^2} = \frac{x^2 - 4x - 1}{(x - 2)^2} [M1] for correct quotient rule setup; [M1] for correct expansion; [A1] for correct simplified answer. [3]


3. (a) y=sin3xy = \sin 3x dydx=3cos3x\frac{dy}{dx} = 3\cos 3x [M1] for chain rule; [A1] for correct answer. [2]

(b) y=e2x+1y = e^{2x+1} dydx=2e2x+1\frac{dy}{dx} = 2e^{2x+1} [M1] for chain rule; [A1] for correct answer. [2]

(c) y=ln(5x2)y = \ln(5x - 2) dydx=55x2\frac{dy}{dx} = \frac{5}{5x - 2} [M1] for chain rule; [A1] for correct answer. [2]


4. y=cos2x=(cosx)2y = \cos^2 x = (\cos x)^2 Using chain rule: let u=cosxu = \cos x, then y=u2y = u^2 dydu=2u\frac{dy}{du} = 2u, dudx=sinx\frac{du}{dx} = -\sin x dydx=2u(sinx)=2cosxsinx=sin2x\frac{dy}{dx} = 2u \cdot (-\sin x) = -2\cos x \sin x = -\sin 2x [M1] for recognising chain rule; [M1] for correct application; [A1] for correct simplified answer (either form acceptable). [3]


5. y=x36x2+9x+4y = x^3 - 6x^2 + 9x + 4 dydx=3x212x+9\frac{dy}{dx} = 3x^2 - 12x + 9 d2ydx2=6x12\frac{d^2y}{dx^2} = 6x - 12 [M1] for first derivative; [M1] for second derivative; [A1] for correct answer. [3]


6. (a) y=x33x2+2y = x^3 - 3x^2 + 2 dydx=3x26x\frac{dy}{dx} = 3x^2 - 6x [A1] for correct derivative. [1]

(b) At x=1x = 1: y=133(1)2+2=13+2=0y = 1^3 - 3(1)^2 + 2 = 1 - 3 + 2 = 0 dydx=3(1)26(1)=36=3\frac{dy}{dx} = 3(1)^2 - 6(1) = 3 - 6 = -3 Gradient of tangent m=3m = -3 Point: (1,0)(1, 0) Equation: y0=3(x1)y - 0 = -3(x - 1) y=3x+3y = -3x + 3 [M1] for finding yy-coordinate; [M1] for finding gradient; [A1] for correct equation. [3]


Section B: Applications of Differentiation (Questions 7–13)

7. y=2x33x212x+7y = 2x^3 - 3x^2 - 12x + 7 dydx=6x26x12\frac{dy}{dx} = 6x^2 - 6x - 12

At stationary points, dydx=0\frac{dy}{dx} = 0: 6x26x12=06x^2 - 6x - 12 = 0 x2x2=0x^2 - x - 2 = 0 (x2)(x+1)=0(x - 2)(x + 1) = 0 x=2x = 2 or x=1x = -1

When x=2x = 2: y=2(8)3(4)12(2)+7=161224+7=13y = 2(8) - 3(4) - 12(2) + 7 = 16 - 12 - 24 + 7 = -13 Stationary point: (2,13)(2, -13)

When x=1x = -1: y=2(1)3(1)12(1)+7=23+12+7=14y = 2(-1) - 3(1) - 12(-1) + 7 = -2 - 3 + 12 + 7 = 14 Stationary point: (1,14)(-1, 14)

Nature: d2ydx2=12x6\frac{d^2y}{dx^2} = 12x - 6

At x=2x = 2: d2ydx2=12(2)6=18>0\frac{d^2y}{dx^2} = 12(2) - 6 = 18 > 0minimum at (2,13)(2, -13)

At x=1x = -1: d2ydx2=12(1)6=18<0\frac{d^2y}{dx^2} = 12(-1) - 6 = -18 < 0maximum at (1,14)(-1, 14)

[M1] for finding dydx\frac{dy}{dx}; [M1] for setting to zero and solving; [M1] for finding yy-coordinates; [M1] for finding d2ydx2\frac{d^2y}{dx^2}; [M1] for testing nature; [A1] for both points and correct nature. [6]


8. (a) y=x2+16x1y = x^2 + 16x^{-1} dydx=2x16x2=2x16x2\frac{dy}{dx} = 2x - 16x^{-2} = 2x - \frac{16}{x^2} [M1] for rewriting; [A1] for correct derivative. [2]

(b) At stationary point, dydx=0\frac{dy}{dx} = 0: 2x16x2=02x - \frac{16}{x^2} = 0 2x=16x22x = \frac{16}{x^2} 2x3=162x^3 = 16 x3=8x^3 = 8 x=2x = 2 (since x>0x > 0)

When x=2x = 2: y=22+162=4+8=12y = 2^2 + \frac{16}{2} = 4 + 8 = 12 Stationary point: (2,12)(2, 12) [M1] for setting derivative to zero; [M1] for solving; [A1] for correct coordinates. [3]

(c) d2ydx2=2+32x3\frac{d^2y}{dx^2} = 2 + \frac{32}{x^3} At x=2x = 2: d2ydx2=2+328=2+4=6>0\frac{d^2y}{dx^2} = 2 + \frac{32}{8} = 2 + 4 = 6 > 0 Since d2ydx2>0\frac{d^2y}{dx^2} > 0, the stationary point is a minimum. [M1] for finding second derivative; [A1] for correct conclusion with justification. [2]


9. (a) y=2x+1x1y = \frac{2x + 1}{x - 1} Quotient rule: u=2x+1u = 2x + 1, v=x1v = x - 1 u=2u' = 2, v=1v' = 1 dydx=2(x1)(2x+1)(1)(x1)2=2x22x1(x1)2=3(x1)2\frac{dy}{dx} = \frac{2(x - 1) - (2x + 1)(1)}{(x - 1)^2} = \frac{2x - 2 - 2x - 1}{(x - 1)^2} = \frac{-3}{(x - 1)^2} [M1] for quotient rule; [A1] for correct simplified derivative. [2]

(b) dydx=3(x1)2\frac{dy}{dx} = \frac{-3}{(x - 1)^2} Since (x1)2>0(x - 1)^2 > 0 for all x1x \neq 1, dydx=3(x1)2<0\frac{dy}{dx} = \frac{-3}{(x - 1)^2} < 0 for all x1x \neq 1. Therefore, dydx\frac{dy}{dx} is never equal to zero, so the curve has no stationary points. [M1] for reasoning about sign of derivative; [A1] for clear conclusion. [2]


10. (a) s=t36t2+9ts = t^3 - 6t^2 + 9t v=dsdt=3t212t+9v = \frac{ds}{dt} = 3t^2 - 12t + 9 When t=2t = 2: v=3(4)12(2)+9=1224+9=3v = 3(4) - 12(2) + 9 = 12 - 24 + 9 = -3 m/s [M1] for differentiating to find velocity; [A1] for correct answer. [2]

(b) a=dvdt=6t12a = \frac{dv}{dt} = 6t - 12 When t=4t = 4: a=6(4)12=2412=12a = 6(4) - 12 = 24 - 12 = 12 m/s² [M1] for differentiating to find acceleration; [A1] for correct answer. [2]

(c) Instantaneously at rest when v=0v = 0: 3t212t+9=03t^2 - 12t + 9 = 0 t24t+3=0t^2 - 4t + 3 = 0 (t1)(t3)=0(t - 1)(t - 3) = 0 t=1t = 1 or t=3t = 3 [M1] for setting v=0v = 0; [A1] for correct times. [2]


11. (a) Volume: V=x2h=500V = x^2h = 500 h=500x2h = \frac{500}{x^2}

Surface area (open top): A=x2+4xhA = x^2 + 4xh (base + 4 sides) A=x2+4x(500x2)=x2+2000xA = x^2 + 4x\left(\frac{500}{x^2}\right) = x^2 + \frac{2000}{x} [M1] for expressing hh in terms of xx; [A1] for correct expression. [2]

(b) A=x2+2000x1A = x^2 + 2000x^{-1} dAdx=2x2000x2=2x2000x2\frac{dA}{dx} = 2x - 2000x^{-2} = 2x - \frac{2000}{x^2}

At minimum, dAdx=0\frac{dA}{dx} = 0: 2x2000x2=02x - \frac{2000}{x^2} = 0 2x=2000x22x = \frac{2000}{x^2} 2x3=20002x^3 = 2000 x3=1000x^3 = 1000 x=10x = 10

Check: d2Adx2=2+4000x3>0\frac{d^2A}{dx^2} = 2 + \frac{4000}{x^3} > 0 for x>0x > 0, so minimum. [M1] for differentiating; [M1] for setting to zero and solving; [A1] for x=10x = 10. [3]

(c) A=102+200010=100+200=300A = 10^2 + \frac{2000}{10} = 100 + 200 = 300 cm² [A1] for correct answer. [1]


12. y=x3+ax2+bx+cy = x^3 + ax^2 + bx + c dydx=3x2+2ax+b\frac{dy}{dx} = 3x^2 + 2ax + b

Stationary point at (2,5)(2, 5): (1) Point lies on curve: 5=8+4a+2b+c5 = 8 + 4a + 2b + c4a+2b+c=34a + 2b + c = -3 (2) Derivative zero at x=2x = 2: 3(4)+2a(2)+b=03(4) + 2a(2) + b = 012+4a+b=012 + 4a + b = 04a+b=124a + b = -12

Passes through (1,3)(1, 3): (3) 3=1+a+b+c3 = 1 + a + b + ca+b+c=2a + b + c = 2

From (2): b=124ab = -12 - 4a Substitute into (1): 4a+2(124a)+c=34a + 2(-12 - 4a) + c = -3 4a248a+c=34a - 24 - 8a + c = -3 4a+c=21-4a + c = 21 ... (4)

Substitute into (3): a+(124a)+c=2a + (-12 - 4a) + c = 2 3a+c=14-3a + c = 14 ... (5)

(4) - (5): (4a+c)(3a+c)=2114(-4a + c) - (-3a + c) = 21 - 14 a=7-a = 7 a=7a = -7

From (5): 3(7)+c=14-3(-7) + c = 1421+c=1421 + c = 14c=7c = -7

From (2): b=124(7)=12+28=16b = -12 - 4(-7) = -12 + 28 = 16

Therefore: a=7a = -7, b=16b = 16, c=7c = -7 [M1] for derivative; [M1] for equation (1); [M1] for equation (2); [M1] for equation (3); [A1] for all three correct values. [5]


13. (a) V=43πr3V = \frac{4}{3}\pi r^3 dVdr=4πr2\frac{dV}{dr} = 4\pi r^2 [A1] for correct derivative. [1]

(b) Given dVdt=100\frac{dV}{dt} = 100 cm³/s. Using chain rule: dVdt=dVdrdrdt\frac{dV}{dt} = \frac{dV}{dr} \cdot \frac{dr}{dt} 100=4πr2drdt100 = 4\pi r^2 \cdot \frac{dr}{dt}

When r=5r = 5: 100=4π(25)drdt100 = 4\pi(25) \cdot \frac{dr}{dt} 100=100πdrdt100 = 100\pi \cdot \frac{dr}{dt} drdt=1π0.318\frac{dr}{dt} = \frac{1}{\pi} \approx 0.318 cm/s [M1] for using chain rule; [M1] for substituting values; [A1] for correct answer. [3]


Section C: Integration (Questions 14–20)

14. (a) (4x36x2+2x1)dx\int (4x^3 - 6x^2 + 2x - 1) \, dx =4x446x33+2x22x+C= \frac{4x^4}{4} - \frac{6x^3}{3} + \frac{2x^2}{2} - x + C =x42x3+x2x+C= x^4 - 2x^3 + x^2 - x + C [M1] for integrating each term; [A1] for correct answer with constant. [2]

(b) (3x2+x1/3)dx\int (3x^{-2} + x^{1/3}) \, dx =3x11+x4/34/3+C= \frac{3x^{-1}}{-1} + \frac{x^{4/3}}{4/3} + C =3x1+34x4/3+C= -3x^{-1} + \frac{3}{4}x^{4/3} + C =3x+34x43+C= -\frac{3}{x} + \frac{3}{4}\sqrt[3]{x^4} + C [M1] for rewriting and integrating; [A1] for correct answer with constant. [2]


15. (a) sin2xdx=12cos2x+C\int \sin 2x \, dx = -\frac{1}{2}\cos 2x + C [M1] for recognising reverse chain rule; [A1] for correct answer. [2]

(b) e3x1dx=13e3x1+C\int e^{3x-1} \, dx = \frac{1}{3}e^{3x-1} + C [M1] for reverse chain rule; [A1] for correct answer. [2]

(c) 12x+5dx=12ln2x+5+C\int \frac{1}{2x + 5} \, dx = \frac{1}{2}\ln|2x + 5| + C [M1] for reverse chain rule; [A1] for correct answer. [2]


16. (a) 13(2x2x+1)dx\int_1^3 (2x^2 - x + 1) \, dx =[2x33x22+x]13= \left[ \frac{2x^3}{3} - \frac{x^2}{2} + x \right]_1^3 =(2(27)392+3)(2(1)312+1)= \left( \frac{2(27)}{3} - \frac{9}{2} + 3 \right) - \left( \frac{2(1)}{3} - \frac{1}{2} + 1 \right) =(184.5+3)(230.5+1)= \left( 18 - 4.5 + 3 \right) - \left( \frac{2}{3} - 0.5 + 1 \right) =16.5(23+0.5)= 16.5 - \left( \frac{2}{3} + 0.5 \right) =16.576= 16.5 - \frac{7}{6} =99676=926=463=1513= \frac{99}{6} - \frac{7}{6} = \frac{92}{6} = \frac{46}{3} = 15\frac{1}{3} [M1] for integration; [M1] for substitution of limits; [A1] for correct answer. [3]

(b) 0π/4cos2xdx\int_0^{\pi/4} \cos 2x \, dx =[12sin2x]0π/4= \left[ \frac{1}{2}\sin 2x \right]_0^{\pi/4} =12sin(π2)12sin(0)= \frac{1}{2}\sin\left(\frac{\pi}{2}\right) - \frac{1}{2}\sin(0) =12(1)0=12= \frac{1}{2}(1) - 0 = \frac{1}{2} [M1] for integration; [M1] for substitution; [A1] for correct answer. [3]


17. f(x)=3x24x+1f'(x) = 3x^2 - 4x + 1 f(x)=(3x24x+1)dx=x32x2+x+Cf(x) = \int (3x^2 - 4x + 1) \, dx = x^3 - 2x^2 + x + C

Passes through (2,10)(2, 10): 10=232(4)+2+C10 = 2^3 - 2(4) + 2 + C 10=88+2+C10 = 8 - 8 + 2 + C 10=2+C10 = 2 + C C=8C = 8

Therefore: f(x)=x32x2+x+8f(x) = x^3 - 2x^2 + x + 8 [M1] for integration; [M1] for substituting point; [M1] for finding constant; [A1] for correct function. [4]


18. y=x24x+3y = x^2 - 4x + 3 Find where curve crosses xx-axis: x24x+3=0x^2 - 4x + 3 = 0 (x1)(x3)=0(x - 1)(x - 3) = 0 x=1x = 1 or x=3x = 3

Between x=0x = 0 and x=2x = 2, the curve crosses the xx-axis at x=1x = 1. For 0x<10 \leq x < 1: y>0y > 0 (above xx-axis) For 1<x21 < x \leq 2: y<0y < 0 (below xx-axis)

Area = 01(x24x+3)dx+12(x24x+3)dx\int_0^1 (x^2 - 4x + 3) \, dx + \left| \int_1^2 (x^2 - 4x + 3) \, dx \right|

(x24x+3)dx=x332x2+3x\int (x^2 - 4x + 3) \, dx = \frac{x^3}{3} - 2x^2 + 3x

01=[x332x2+3x]01=(132+3)0=43\int_0^1 = \left[ \frac{x^3}{3} - 2x^2 + 3x \right]_0^1 = \left( \frac{1}{3} - 2 + 3 \right) - 0 = \frac{4}{3}

12=[x332x2+3x]12\int_1^2 = \left[ \frac{x^3}{3} - 2x^2 + 3x \right]_1^2 =(838+6)(132+3)= \left( \frac{8}{3} - 8 + 6 \right) - \left( \frac{1}{3} - 2 + 3 \right) =(832)(13+1)= \left( \frac{8}{3} - 2 \right) - \left( \frac{1}{3} + 1 \right) =2343=23= \frac{2}{3} - \frac{4}{3} = -\frac{2}{3}

Total area = 43+23=43+23=2\frac{4}{3} + \left| -\frac{2}{3} \right| = \frac{4}{3} + \frac{2}{3} = 2 square units. [M1] for finding xx-intercepts; [M1] for splitting integral; [M1] for integration; [M1] for evaluating; [A1] for correct total area. [5]


19. y=4xx2y = 4x - x^2 Curve meets xx-axis when y=0y = 0: 4xx2=04x - x^2 = 0 x(4x)=0x(4 - x) = 0 x=0x = 0 or x=4x = 4

Area = 04(4xx2)dx\int_0^4 (4x - x^2) \, dx =[2x2x33]04= \left[ 2x^2 - \frac{x^3}{3} \right]_0^4 =(2(16)643)0= \left( 2(16) - \frac{64}{3} \right) - 0 =32643= 32 - \frac{64}{3} =963643=323= \frac{96}{3} - \frac{64}{3} = \frac{32}{3} square units. [M1] for finding limits; [M1] for integration; [M1] for substitution; [A1] for correct answer. [4]


20. (a) v=6tt2v = 6t - t^2 Displacement s=04(6tt2)dts = \int_0^4 (6t - t^2) \, dt =[3t2t33]04= \left[ 3t^2 - \frac{t^3}{3} \right]_0^4 =(3(16)643)0= \left( 3(16) - \frac{64}{3} \right) - 0 =48643=1443643=80326.7= 48 - \frac{64}{3} = \frac{144}{3} - \frac{64}{3} = \frac{80}{3} \approx 26.7 m [M1] for integrating; [M1] for evaluating; [A1] for correct answer. [3]

(b) Total distance = 06vdt\int_0^6 |v| \, dt Find when v=0v = 0: 6tt2=06t - t^2 = 0 t(6t)=0t(6 - t) = 0 t=0t = 0 or t=6t = 6

For 0t60 \leq t \leq 6: v0v \geq 0 (since 6tt2=t(6t)06t - t^2 = t(6 - t) \geq 0) So v=v|v| = v for 0t60 \leq t \leq 6.

Total distance = 06(6tt2)dt\int_0^6 (6t - t^2) \, dt =[3t2t33]06= \left[ 3t^2 - \frac{t^3}{3} \right]_0^6 =(3(36)2163)0= \left( 3(36) - \frac{216}{3} \right) - 0 =10872=36= 108 - 72 = 36 m [M1] for finding when v=0v = 0; [M1] for determining sign of vv; [M1] for integrating; [A1] for correct total distance. [4]


END OF ANSWER KEY