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.

2,251.

At what value of x is the function x\(^2\) + x + 1 minimum?

A.

-1

B.

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

C.

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

D.

1

Correct answer is B

x\(^2\) + x + 1

\(\frac{dy}{dx}\) = 2x + 1

At the turning point, \(\frac{dy}{dx}\) = 0

2x + 1 = 0

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

2,252.

Find the sum of the first 18 terms of the progression 3, 6, 12......

A.

3(217 - 1)

B.

3(218 - 1)

C.

3(218 + 1)

D.

3(217 - 1)

Correct answer is B

3 + 6 + 12 + .....18thy term

1st term = 3, common ratio \(\frac{6}{3}\) = 2

n = 18, sum of GP is given by Sn = a\(\frac{(r^n - 1)}{r - 1}\)

s18 = 3\(\frac{(2^{18} - 1)}{2 - 1}\)

= 3(2^18 - 1)

2,253.

Find the sum of the first twenty terms of the progression log a, log a2, log a3.....

A.

log a20

B.

log a21

C.

log a200

D.

log a210

Correct answer is D

No explanation has been provided for this answer.

2,254.

Given that x2 + y2 + z2 = 194, calculate z if x = 7 and \(\sqrt{y}\) = 3

A.

\(\sqrt{10}\)

B.

8

C.

12.2

D.

13.4

Correct answer is B

Given that x2 + y2 + z2 = 194, calculate z if x = 7 and \(\sqrt{y}\) = 3

x = 7

∴ x2 = 49

\(\sqrt{y}\) = 3

∴ y2 = 81 = x2 + y2 + z2 = 194

49 + 81 + z2 = 194

130 + z2 = 194

z2 = 194 - 130

= 64

z = \(\sqrt{64}\)

= 8

2,255.

Simplify \(\frac{x}{x + y}\) + \(\frac{y}{x - y}\) - \(\frac{x^2}{x^2 - y^2}\)

A.

\(\frac{x}{x^2 - y^2}\)

B.

\(\frac{y^2}{x^2 - y^2}\)

C.

\(\frac{x^2}{x^2 - y^2}\)

D.

\(\frac{y}{x^2 - y^2}\)

Correct answer is B

\(\frac{x}{x + y}\) + \(\frac{y}{x - y}\) - \(\frac{x^2}{x^2 - y^2}\)

\(\frac{x}{x + y}\) + \(\frac{y}{x - y}\) - \(\frac{x^2}{(x + y)(x - y}\)

= \(\frac{x(x - y) + y(x + y) - x^2}{(x + y)(x - y}\)

= \(\frac{x^2 + xy + xy + y^2 - x^2}{(x + y)(x - y}\)

= \(\frac{y^2}{(x + y)(x - y)}\)

= \(\frac{y^2}{(x^2 - y^2)}\)