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Secondary 4 Additional Mathematics Calculus Quiz

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Secondary 4 Additional Mathematics From Real Exams Generated by DeepSeek V4 Pro Updated 2026-06-03

Questions

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Secondary 4 Additional Mathematics Quiz - Calculus

Name: ________________________
Class: ________________________
Date: ________________________
Score: ______ / 60

Duration: 1 hour 15 minutes
Total Marks: 60

Instructions:

  • Answer ALL questions in the spaces provided.
  • Show all working clearly. Marks are awarded for method.
  • Unless otherwise stated, give non-exact answers correct to 3 significant figures.
  • You are reminded of the need for clear presentation in your answers.
  • The number of marks is given in brackets [ ] at the end of each question or part question.

Section A: Differentiation Techniques (15 marks)

Answer ALL questions in this section.

1. Differentiate each of the following with respect to xx:

(a) y=3x42x3+5x7y = 3x^4 - 2x^3 + 5x - 7 [2]

 
 
 
 

(b) y=(2x+1)(x23)y = (2x + 1)(x^2 - 3) [3]

 
 
 
 
 


2. Find dydx\frac{dy}{dx} for each of the following:

(a) y=x2+12x1y = \frac{x^2 + 1}{2x - 1}, x12x \neq \frac{1}{2} [3]

 
 
 
 
 

(b) y=3x2+4y = \sqrt{3x^2 + 4} [2]

 
 
 
 


3. A curve has equation y=4x+ln(2x)y = \frac{4}{x} + \ln(2x), where x>0x > 0.

Find the gradient of the curve at the point where x=2x = 2. [3]

 
 
 
 
 


4. Given that y=e2xsinxy = e^{2x} \sin x, find dydx\frac{dy}{dx} in its simplest form. [2]

 
 
 
 


5. Differentiate y=cosx1+sinxy = \frac{\cos x}{1 + \sin x} with respect to xx. [3]

 
 
 
 
 


Section B: Applications of Differentiation (15 marks)

Answer ALL questions in this section.

6. A curve has equation y=x36x2+9x+1y = x^3 - 6x^2 + 9x + 1.

(a) Find the coordinates of the stationary points of the curve. [4]

 
 
 
 
 
 

(b) Determine the nature of each stationary point. [3]

 
 
 
 
 
 


7. The equation of a curve is y=2x33x212x+7y = 2x^3 - 3x^2 - 12x + 7.

(a) Find the range of values of xx for which the curve is increasing. [3]

 
 
 
 
 
 

(b) Find the equation of the tangent to the curve at the point where x=1x = 1. [3]

 
 
 
 
 
 


8. A rectangular box with a square base and an open top is to have a volume of 500 cm3500 \text{ cm}^3. The length of each side of the base is x cmx \text{ cm} and the height is h cmh \text{ cm}.

(a) Show that the external surface area, A cm2A \text{ cm}^2, is given by A=x2+2000xA = x^2 + \frac{2000}{x}. [2]

 
 
 
 
 


9. A curve has equation y=x33x2+2y = x^3 - 3x^2 + 2. Find the coordinates of the point of inflection. [3]

 
 
 
 
 
 


10. The radius of a circle is increasing at a constant rate of 0.5 cm/s0.5 \text{ cm/s}. Find the rate of increase of the area of the circle when the radius is 4 cm4 \text{ cm}. [3]

 
 
 
 
 
 


Section C: Integration (15 marks)

Answer ALL questions in this section.

11. Find each of the following integrals:

(a) (6x24x+3)dx\displaystyle \int (6x^2 - 4x + 3) \, dx [2]

 
 
 
 

(b) (2x+3ex)dx\displaystyle \int \left( \frac{2}{x} + 3e^x \right) dx, x>0x > 0 [2]

 
 
 
 

(c) (2x1)4dx\displaystyle \int (2x - 1)^4 \, dx [3]

 
 
 
 
 


12. Evaluate:

(a) 14(x+1x2)dx\displaystyle \int_1^4 \left( \sqrt{x} + \frac{1}{x^2} \right) dx [4]

 
 
 
 
 
 
 

(b) 0π6cos2xdx\displaystyle \int_0^{\frac{\pi}{6}} \cos 2x \, dx [3]

 
 
 
 
 
 


13. A curve passes through the point (1,5)(1, 5) and has gradient function dydx=3x22x+1\frac{dy}{dx} = 3x^2 - 2x + 1.

Find the equation of the curve. [3]

 
 
 
 
 
 


14. Find sin2xdx\displaystyle \int \sin^2 x \, dx. [3]

 
 
 
 
 
 


15. Evaluate 012xx2+1dx\displaystyle \int_0^1 \frac{2x}{x^2 + 1} \, dx. [3]

 
 
 
 
 
 


Section D: Applications of Integration (15 marks)

Answer ALL questions in this section.

16. The diagram shows the curve y=4xx2y = 4x - x^2 and the line y=3y = 3.

Curve and line

(a) Find the coordinates of the points AA and BB where the curve meets the line. [3]

 
 
 
 
 

(b) Find the area of the shaded region bounded by the curve and the line. [5]

 
 
 
 
 
 
 
 


17. A curve has equation y=1x2y = \frac{1}{x^2} for x1x \geq 1. Find the volume of revolution when the region bounded by the curve, the xx-axis, and the lines x=1x = 1 and x=2x = 2 is rotated completely about the xx-axis. [4]

 
 
 
 
 
 
 


18. The velocity v m/sv \text{ m/s} of a particle at time tt seconds is given by v=3t24t+1v = 3t^2 - 4t + 1. Find the distance travelled by the particle between t=1t = 1 and t=3t = 3. [3]

 
 
 
 
 
 


19. Find the area of the region bounded by the curve y=sinxy = \sin x, the xx-axis, and the lines x=0x = 0 and x=πx = \pi. [3]

 
 
 
 
 
 


20. The region bounded by the curve y=xy = \sqrt{x}, the xx-axis, and the line x=4x = 4 is rotated completely about the xx-axis. Find the volume of the solid formed. [3]

 
 
 
 
 
 


END OF QUIZ

Check your work carefully.

Answers

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Secondary 4 Additional Mathematics Quiz - Calculus — ANSWER KEY

Total Marks: 60


Section A: Differentiation Techniques (15 marks)

1. (a) y=3x42x3+5x7y = 3x^4 - 2x^3 + 5x - 7 [2 marks]

dydx=12x36x2+5\frac{dy}{dx} = 12x^3 - 6x^2 + 5

Marking: M1 for correct differentiation of at least 3 terms; A1 for fully correct answer. Deduct 1 mark for each error.


1. (b) y=(2x+1)(x23)y = (2x + 1)(x^2 - 3) [3 marks]

Method 1 (Product Rule): Let u=2x+1u = 2x + 1, v=x23v = x^2 - 3 dudx=2\frac{du}{dx} = 2, dvdx=2x\frac{dv}{dx} = 2x

dydx=udvdx+vdudx=(2x+1)(2x)+(x23)(2)\frac{dy}{dx} = u\frac{dv}{dx} + v\frac{du}{dx} = (2x + 1)(2x) + (x^2 - 3)(2) =4x2+2x+2x26=6x2+2x6= 4x^2 + 2x + 2x^2 - 6 = 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

Marking: M1 for product rule or expansion; M1 for correct application; A1 for simplified answer.


2. (a) y=x2+12x1y = \frac{x^2 + 1}{2x - 1} [3 marks]

Using Quotient Rule: u=x2+1u = x^2 + 1, v=2x1v = 2x - 1 dudx=2x\frac{du}{dx} = 2x, dvdx=2\frac{dv}{dx} = 2

dydx=vdudxudvdxv2=(2x1)(2x)(x2+1)(2)(2x1)2\frac{dy}{dx} = \frac{v\frac{du}{dx} - u\frac{dv}{dx}}{v^2} = \frac{(2x - 1)(2x) - (x^2 + 1)(2)}{(2x - 1)^2} =4x22x2x22(2x1)2=2x22x2(2x1)2= \frac{4x^2 - 2x - 2x^2 - 2}{(2x - 1)^2} = \frac{2x^2 - 2x - 2}{(2x - 1)^2}

Marking: M1 for quotient rule formula; M1 for correct substitution; A1 for simplified numerator.


2. (b) y=3x2+4=(3x2+4)12y = \sqrt{3x^2 + 4} = (3x^2 + 4)^{\frac{1}{2}} [2 marks]

Using Chain Rule: dydx=12(3x2+4)126x=3x3x2+4\frac{dy}{dx} = \frac{1}{2}(3x^2 + 4)^{-\frac{1}{2}} \cdot 6x = \frac{3x}{\sqrt{3x^2 + 4}}

Marking: M1 for chain rule with correct derivative of inside function; A1 for simplified answer.


3. y=4x+ln(2x)=4x1+ln(2x)y = \frac{4}{x} + \ln(2x) = 4x^{-1} + \ln(2x), x>0x > 0 [3 marks]

dydx=4x2+1x=4x2+1x\frac{dy}{dx} = -4x^{-2} + \frac{1}{x} = -\frac{4}{x^2} + \frac{1}{x}

At x=2x = 2: dydxx=2=44+12=1+12=12\frac{dy}{dx}\bigg|_{x=2} = -\frac{4}{4} + \frac{1}{2} = -1 + \frac{1}{2} = -\frac{1}{2}

Marking: M1 for derivative of 4/x4/x; M1 for derivative of ln(2x)\ln(2x); A1 for correct gradient 12-\frac{1}{2}.


4. y=e2xsinxy = e^{2x} \sin x [2 marks]

Using Product Rule: u=e2xu = e^{2x}, v=sinxv = \sin x dudx=2e2x\frac{du}{dx} = 2e^{2x}, dvdx=cosx\frac{dv}{dx} = \cos x

dydx=e2xcosx+sinx2e2x=e2x(cosx+2sinx)\frac{dy}{dx} = e^{2x} \cos x + \sin x \cdot 2e^{2x} = e^{2x}(\cos x + 2\sin x)

Marking: M1 for product rule with correct derivatives; A1 for simplified factored form.


5. y=cosx1+sinxy = \frac{\cos x}{1 + \sin x} [3 marks]

Using Quotient Rule: u=cosxu = \cos x, v=1+sinxv = 1 + \sin x dudx=sinx\frac{du}{dx} = -\sin x, dvdx=cosx\frac{dv}{dx} = \cos x

dydx=(1+sinx)(sinx)cosx(cosx)(1+sinx)2\frac{dy}{dx} = \frac{(1 + \sin x)(-\sin x) - \cos x(\cos x)}{(1 + \sin x)^2} =sinxsin2xcos2x(1+sinx)2= \frac{-\sin x - \sin^2 x - \cos^2 x}{(1 + \sin x)^2} =sinx(sin2x+cos2x)(1+sinx)2= \frac{-\sin x - (\sin^2 x + \cos^2 x)}{(1 + \sin x)^2} =sinx1(1+sinx)2=1+sinx(1+sinx)2=11+sinx= \frac{-\sin x - 1}{(1 + \sin x)^2} = -\frac{1 + \sin x}{(1 + \sin x)^2} = -\frac{1}{1 + \sin x}

Marking: M1 for quotient rule; M1 for correct simplification using identity; A1 for final answer.


Section B: Applications of Differentiation (15 marks)

6. (a) y=x36x2+9x+1y = x^3 - 6x^2 + 9x + 1 [4 marks]

dydx=3x212x+9\frac{dy}{dx} = 3x^2 - 12x + 9

For stationary points, dydx=0\frac{dy}{dx} = 0: 3x212x+9=03x^2 - 12x + 9 = 0 x24x+3=0x^2 - 4x + 3 = 0 (x1)(x3)=0(x - 1)(x - 3) = 0 x=1 or x=3x = 1 \text{ or } x = 3

When x=1x = 1: y=16+9+1=5y = 1 - 6 + 9 + 1 = 5(1,5)(1, 5) When x=3x = 3: y=2754+27+1=1y = 27 - 54 + 27 + 1 = 1(3,1)(3, 1)

Stationary points: (1,5)(1, 5) and (3,1)(3, 1)

Marking: M1 for differentiation; M1 for setting to zero; M1 for solving quadratic; A1 for both coordinates.


6. (b) [3 marks]

d2ydx2=6x12\frac{d^2y}{dx^2} = 6x - 12

At x=1x = 1: d2ydx2=6(1)12=6<0\frac{d^2y}{dx^2} = 6(1) - 12 = -6 < 0Maximum point

At x=3x = 3: d2ydx2=6(3)12=6>0\frac{d^2y}{dx^2} = 6(3) - 12 = 6 > 0Minimum point

Marking: M1 for second derivative; M1 for evaluating at both points; A1 for correct nature of both points.


7. (a) y=2x33x212x+7y = 2x^3 - 3x^2 - 12x + 7 [3 marks]

dydx=6x26x12\frac{dy}{dx} = 6x^2 - 6x - 12

Curve is increasing when 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

Solution: x<1x < -1 or x>2x > 2

Marking: M1 for differentiation; M1 for factorising and solving inequality; A1 for correct intervals.


7. (b) [3 marks]

At x=1x = 1: y=2(1)33(1)212(1)+7=2312+7=6y = 2(1)^3 - 3(1)^2 - 12(1) + 7 = 2 - 3 - 12 + 7 = -6

Gradient at x=1x = 1: dydx=6(1)26(1)12=6612=12\frac{dy}{dx} = 6(1)^2 - 6(1) - 12 = 6 - 6 - 12 = -12

Equation of tangent: y(6)=12(x1)y - (-6) = -12(x - 1) y+6=12x+12y + 6 = -12x + 12 y=12x+6y = -12x + 6

Marking: M1 for finding point; M1 for finding gradient; A1 for correct equation.


8. (a) [2 marks]

Volume: V=x2h=500V = x^2 h = 500h=500x2h = \frac{500}{x^2}

Surface area (open top): A=x2+4xhA = x^2 + 4xh A=x2+4x(500x2)=x2+2000xA = x^2 + 4x\left(\frac{500}{x^2}\right) = x^2 + \frac{2000}{x}

Marking: M1 for expressing hh in terms of xx; A1 for showing A=x2+2000xA = x^2 + \frac{2000}{x}.


9. y=x33x2+2y = x^3 - 3x^2 + 2 [3 marks]

dydx=3x26x\frac{dy}{dx} = 3x^2 - 6x d2ydx2=6x6\frac{d^2y}{dx^2} = 6x - 6

For point of inflection, d2ydx2=0\frac{d^2y}{dx^2} = 0: 6x6=0    x=16x - 6 = 0 \implies x = 1

Check sign change of d2ydx2\frac{d^2y}{dx^2}: For x<1x < 1, e.g. x=0x = 0: d2ydx2=6<0\frac{d^2y}{dx^2} = -6 < 0 For x>1x > 1, e.g. x=2x = 2: d2ydx2=6>0\frac{d^2y}{dx^2} = 6 > 0 Sign changes, so point of inflection at x=1x = 1.

When x=1x = 1: y=13+2=0y = 1 - 3 + 2 = 0

Point of inflection: (1,0)(1, 0)

Marking: M1 for second derivative; M1 for setting to zero and solving; A1 for coordinates with justification.


10. [3 marks]

A=πr2A = \pi r^2, drdt=0.5 cm/s\frac{dr}{dt} = 0.5 \text{ cm/s}

dAdt=2πrdrdt\frac{dA}{dt} = 2\pi r \frac{dr}{dt}

When r=4r = 4: dAdt=2π(4)(0.5)=4π cm2/s\frac{dA}{dt} = 2\pi (4)(0.5) = 4\pi \text{ cm}^2\text{/s}

Marking: M1 for dAdt=2πrdrdt\frac{dA}{dt} = 2\pi r \frac{dr}{dt}; M1 for substitution; A1 for 4π cm2/s4\pi \text{ cm}^2\text{/s}.


Section C: Integration (15 marks)

11. (a) (6x24x+3)dx\displaystyle \int (6x^2 - 4x + 3) \, dx [2 marks]

=6x334x22+3x+C= 6 \cdot \frac{x^3}{3} - 4 \cdot \frac{x^2}{2} + 3x + C =2x32x2+3x+C= 2x^3 - 2x^2 + 3x + C

Marking: M1 for integrating at least 2 terms correctly; A1 for fully correct answer including constant.


11. (b) (2x+3ex)dx\displaystyle \int \left( \frac{2}{x} + 3e^x \right) dx, x>0x > 0 [2 marks]

=2lnx+3ex+C= 2\ln|x| + 3e^x + C =2lnx+3ex+C(since x>0)= 2\ln x + 3e^x + C \quad (\text{since } x > 0)

Marking: M1 for correct integration of one term; A1 for fully correct including constant.


11. (c) (2x1)4dx\displaystyle \int (2x - 1)^4 \, dx [3 marks]

Let u=2x1u = 2x - 1, dudx=2\frac{du}{dx} = 2, dx=du2dx = \frac{du}{2}

(2x1)4dx=u4du2=12u55+C\int (2x - 1)^4 \, dx = \int u^4 \cdot \frac{du}{2} = \frac{1}{2} \cdot \frac{u^5}{5} + C =(2x1)510+C= \frac{(2x - 1)^5}{10} + C

Marking: M1 for substitution or recognising chain rule; M1 for correct integration; A1 for simplified answer.


12. (a) 14(x+1x2)dx\displaystyle \int_1^4 \left( \sqrt{x} + \frac{1}{x^2} \right) dx [4 marks]

=14(x12+x2)dx= \int_1^4 \left( x^{\frac{1}{2}} + x^{-2} \right) dx =[x3232+x11]14= \left[ \frac{x^{\frac{3}{2}}}{\frac{3}{2}} + \frac{x^{-1}}{-1} \right]_1^4 =[23x321x]14= \left[ \frac{2}{3}x^{\frac{3}{2}} - \frac{1}{x} \right]_1^4 =(23(4)3214)(23(1)321)= \left( \frac{2}{3}(4)^{\frac{3}{2}} - \frac{1}{4} \right) - \left( \frac{2}{3}(1)^{\frac{3}{2}} - 1 \right) =(23814)(231)= \left( \frac{2}{3} \cdot 8 - \frac{1}{4} \right) - \left( \frac{2}{3} - 1 \right) =(16314)(13)= \left( \frac{16}{3} - \frac{1}{4} \right) - \left( -\frac{1}{3} \right) =16314+13=17314= \frac{16}{3} - \frac{1}{4} + \frac{1}{3} = \frac{17}{3} - \frac{1}{4} =68312=6512= \frac{68 - 3}{12} = \frac{65}{12}

Marking: M1 for correct integration; M1 for correct limits substitution; M1 for correct evaluation; A1 for 6512\frac{65}{12}.


12. (b) 0π6cos2xdx\displaystyle \int_0^{\frac{\pi}{6}} \cos 2x \, dx [3 marks]

=[sin2x2]0π6= \left[ \frac{\sin 2x}{2} \right]_0^{\frac{\pi}{6}} =sin(π3)2sin(0)2= \frac{\sin(\frac{\pi}{3})}{2} - \frac{\sin(0)}{2} =3220=34= \frac{\frac{\sqrt{3}}{2}}{2} - 0 = \frac{\sqrt{3}}{4}

Marking: M1 for correct integration; M1 for correct substitution of limits; A1 for 34\frac{\sqrt{3}}{4}.


13. dydx=3x22x+1\frac{dy}{dx} = 3x^2 - 2x + 1, passes through (1,5)(1, 5) [3 marks]

y=(3x22x+1)dx=x3x2+x+Cy = \int (3x^2 - 2x + 1) \, dx = x^3 - x^2 + x + C

Substitute (1,5)(1, 5): 5=1312+1+C5 = 1^3 - 1^2 + 1 + C 5=11+1+C5 = 1 - 1 + 1 + C C=4C = 4

Equation: y=x3x2+x+4y = x^3 - x^2 + x + 4

Marking: M1 for integration; M1 for using point to find CC; A1 for correct equation.


14. sin2xdx\displaystyle \int \sin^2 x \, dx [3 marks]

Using identity sin2x=1cos2x2\sin^2 x = \frac{1 - \cos 2x}{2}:

sin2xdx=1cos2x2dx\int \sin^2 x \, dx = \int \frac{1 - \cos 2x}{2} \, dx =12(1cos2x)dx= \frac{1}{2} \int (1 - \cos 2x) \, dx =12(xsin2x2)+C= \frac{1}{2} \left( x - \frac{\sin 2x}{2} \right) + C =x2sin2x4+C= \frac{x}{2} - \frac{\sin 2x}{4} + C

Marking: M1 for using correct identity; M1 for integration; A1 for final answer with constant.


15. 012xx2+1dx\displaystyle \int_0^1 \frac{2x}{x^2 + 1} \, dx [3 marks]

Let u=x2+1u = x^2 + 1, dudx=2x\frac{du}{dx} = 2x, du=2xdxdu = 2x \, dx

When x=0x = 0, u=1u = 1; when x=1x = 1, u=2u = 2

012xx2+1dx=121udu\int_0^1 \frac{2x}{x^2 + 1} \, dx = \int_1^2 \frac{1}{u} \, du =[lnu]12=ln2ln1=ln2= \left[ \ln|u| \right]_1^2 = \ln 2 - \ln 1 = \ln 2

Marking: M1 for substitution; M1 for correct limits and integration; A1 for ln2\ln 2.


Section D: Applications of Integration (15 marks)

16. (a) Curve: y=4xx2y = 4x - x^2, Line: y=3y = 3 [3 marks]

At intersection: 4xx2=34x - x^2 = 3 x24x+3=0x^2 - 4x + 3 = 0 (x1)(x3)=0(x - 1)(x - 3) = 0 x=1x = 1 or x=3x = 3

When x=1x = 1: y=3y = 3A(1,3)A(1, 3) When x=3x = 3: y=3y = 3B(3,3)B(3, 3)

Marking: M1 for equating; M1 for solving quadratic; A1 for both coordinates.


16. (b) [5 marks]

Area = 13[(4xx2)3]dx\displaystyle \int_1^3 \left[ (4x - x^2) - 3 \right] dx

=13(4xx23)dx= \int_1^3 (4x - x^2 - 3) \, dx =[2x2x333x]13= \left[ 2x^2 - \frac{x^3}{3} - 3x \right]_1^3 =(2(9)2739)(2(1)133)= \left( 2(9) - \frac{27}{3} - 9 \right) - \left( 2(1) - \frac{1}{3} - 3 \right) =(1899)(2133)= (18 - 9 - 9) - \left( 2 - \frac{1}{3} - 3 \right) =0(43)=43 square units= 0 - \left( -\frac{4}{3} \right) = \frac{4}{3} \text{ square units}

Marking: M1 for correct integral expression (curve minus line); M1 for integration; M1 for correct limits; M1 for correct evaluation; A1 for 43\frac{4}{3}.


17. y=1x2y = \frac{1}{x^2}, x1x \geq 1, rotated about xx-axis from x=1x = 1 to x=2x = 2 [4 marks]

Volume V=π12y2dx=π121x4dxV = \pi \int_1^2 y^2 \, dx = \pi \int_1^2 \frac{1}{x^4} \, dx

=π12x4dx= \pi \int_1^2 x^{-4} \, dx =π[x33]12= \pi \left[ \frac{x^{-3}}{-3} \right]_1^2 =π[13x3]12= \pi \left[ -\frac{1}{3x^3} \right]_1^2 =π(13(8)(13(1)))= \pi \left( -\frac{1}{3(8)} - \left( -\frac{1}{3(1)} \right) \right) =π(124+13)= \pi \left( -\frac{1}{24} + \frac{1}{3} \right) =π(1+824)=7π24 cubic units= \pi \left( \frac{-1 + 8}{24} \right) = \frac{7\pi}{24} \text{ cubic units}

Marking: M1 for correct volume formula; M1 for correct integration; M1 for correct limits; A1 for 7π24\frac{7\pi}{24}.


18. v=3t24t+1v = 3t^2 - 4t + 1, t=1t = 1 to t=3t = 3 [3 marks]

Distance = 13vdt\displaystyle \int_1^3 |v| \, dt. First check if vv changes sign.

v=3t24t+1=(3t1)(t1)v = 3t^2 - 4t + 1 = (3t - 1)(t - 1) For 1t31 \leq t \leq 3, v0v \geq 0 (since t10t - 1 \geq 0 and 3t1>03t - 1 > 0).

Distance = 13(3t24t+1)dt\displaystyle \int_1^3 (3t^2 - 4t + 1) \, dt =[t32t2+t]13= \left[ t^3 - 2t^2 + t \right]_1^3 =(2718+3)(12+1)= (27 - 18 + 3) - (1 - 2 + 1) =120=12 m= 12 - 0 = 12 \text{ m}

Marking: M1 for checking sign or integrating; M1 for correct integration and limits; A1 for 12.


19. Area bounded by y=sinxy = \sin x, xx-axis, x=0x = 0, x=πx = \pi [3 marks]

Area = 0πsinxdx\displaystyle \int_0^\pi \sin x \, dx =[cosx]0π= \left[ -\cos x \right]_0^\pi =(cosπ)(cos0)= (-\cos \pi) - (-\cos 0) =((1))(1)=1+1=2 square units= (-(-1)) - (-1) = 1 + 1 = 2 \text{ square units}

Marking: M1 for correct integral; M1 for correct integration and limits; A1 for 2.


20. y=xy = \sqrt{x}, rotated about xx-axis from x=0x = 0 to x=4x = 4 [3 marks]

Volume V=π04(x)2dx=π04xdxV = \pi \int_0^4 (\sqrt{x})^2 \, dx = \pi \int_0^4 x \, dx =π[x22]04= \pi \left[ \frac{x^2}{2} \right]_0^4 =π(1620)=8π cubic units= \pi \left( \frac{16}{2} - 0 \right) = 8\pi \text{ cubic units}

Marking: M1 for correct volume formula; M1 for integration and limits; A1 for 8π8\pi.


END OF ANSWER KEY