Mathematics questions and answers

Mathematics Questions and Answers

How good are you with figures and formulas? Find out with these Mathematics past questions and answers. This Test is useful for both job aptitude test candidates and students preparing for JAMB, WAEC, NECO or Post UTME.

2,326.

Evaluate the integral \(\int^{\frac{\pi}{4}}_{\frac{\pi}{12}} 2 \cos 2x \mathrm {d} x\)

A.

-\(\frac{1}{2}\)

B.

-1

C.

\(\frac{1}{2}\)

D.

1

Correct answer is C

\(\int_{\frac{\pi}{12}} ^{\frac{\pi}{4}} 2 \cos 2x \mathrm {d} x\)

= \([\frac{2 \sin 2x}{2}]|_{\frac{\pi}{12}} ^{\frac{\pi}{4}}\)

= \(\sin 2x |_{\frac{\pi}{12}} ^{\frac{\pi}{4}}\)

= \(\sin 2(\frac{\pi}{4}) - \sin 2(\frac{\pi}{12})\)

= \(\sin \frac{\pi}{2} - \sin \frac{\pi}{6}\)

= \(1 - \frac{1}{2} = \frac{1}{2}\)

2,327.

A student blows a balloon and its volume increases at a rate of \(\pi\)(20 - t2)cm3S-1 after t seconds. If the initial volume is 0 cm3, find the volume of the balloon after 2 seconds

A.

37.00\(\pi\)

B.

37.33\(\pi\)

C.

40.00\(\pi\)

D.

42.67\(\pi\)

Correct answer is B

\(\frac{dv}{dt}\) = \(\pi\)(20 - t2)cm2S-1

\(\int\)dv = \(\pi\)(20 - t2)dt

V = \(\pi\) \(\int\)(20 - t2)dt

V = \(\pi\)(20 \(\frac{t}{3}\) - t3) + c

when c = 0, V = (20t - \(\frac{t^3}{3}\))

after t = 2 seconds

V = \(\pi\)(40 - \(\frac{8}{3}\)

= \(\pi\)\(\frac{120 - 8}{3}\)

= \(\frac{112}{3}\)

= 37.33\(\pi\)

2,328.

Obtain a maximum value of the function f(x) x3 - 12x + 11

A.

-5

B.

-2

C.

2

D.

27

Correct answer is D

f(x) = x3 - 12x + 11

\(\frac{df(x)}{dx)}\) = 3x2 - 12 = 0

∴ 3x2 - 12 = 0 \(\to\) x2m = 4

x = \(\pm\)2, f(+2) = 8 - 24 + 11 = -15

= f(-2) = (-8) + 24 + 11

= 35 - 8 = 27

∴ maximum value = 27

2,329.

Ice forms on a refrigerator ice-box at the rate of (4 - 06t)g per minute after t minutes. If initially there are 2g of ice in the box, find the mass of ice formed in 5 minutes

A.

19.5

B.

17.0

C.

14.5

D.

12.5

Correct answer is C

\(\frac{dm}{dt}\) = 4 - 0.6t

\(\int\)dm = \(\int\)(4 - 0.6t)dt

m = \(4t - 0.3t^2 + c\), when t = 0, m = 2g

∴ c = 2

m = \(4t - 0.3t^2 + 2\), when t = 5 minutes

m = \(4(5) - 0.3(5)^2 + 2 = 20 - 7.5 + 2\)

= 14.5

2,330.

If y = x sin x, Find \(\frac{d^2 y}{d^2 x}\)

A.

2 cosx - x sinx

B.

sinx + x cosx

C.

sinx - x cosx

D.

x sinx - 2 cosx

Correct answer is A

\(y = x \sin x\)

\(\frac{\mathrm d y}{\mathrm d x} = x \cos x + \sin x\)

\(\frac{\mathrm d^{2} y}{\mathrm d x^{2}} = x (- \sin x) + \cos x + \cos x\)

= \(2 \cos x - x \sin x\)