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.

1,991.

The value of (0.03)3 - (0.02)3 is

A.

0.019

B.

0.0019

C.

0.00019

D.

0.000019

E.

0.000035

Correct answer is D

Using the method of difference of two cubes,

\(a^{3} - b^{3} = (a - b)(a^{2} + ab + b^{2})\)

\((0.03)^{3} - (0.02)^{3} = (0.03 - 0.02)((0.03)^{2} + (0.03)(0.02) + (0.02)^{2}\)

= \((0.01)(0.0009 + 0.0006 + 0.0004)\)

= \(0.01 \times 0.0019\)

= \(0.000019\)

1,992.

Make T the subject of the equation \(\frac{av}{1 - v}\) = \(\sqrt{\frac{2v + T}{a + 2T}}\)

A.

T = \(\frac{3av}{1 - v}\)

B.

T = \(\frac{1 + v}{2a^2v^3}\)

C.

T = \(\frac{2v(1 - v)^3 - a^4v^3}{2a^3v^3 + (1 - v)^2}\)

D.

\(\frac{2v(1 - v)^3 - a^4 v^3}{2a^3v^ 3 - (1 - v)^3}\)

Correct answer is D

\(\frac{av}{1 - v}\) = \(\sqrt{\frac{2v + T}{a + 2T}}\)

\(\frac{(av)^3}{(1 - v)^3}\) = \(\frac{2v + T}{a + 2T}\)

\(\frac{a^3v^3}{(1^3 - v)^3}\) = \(\frac{2v + T}{a + 2T}\)

= \(\frac{2v(1 - v)^3 - a^4 v^3}{2a^3v^ 3 - (1 - v)^3}\)

1,993.

If (x + 2) and (x - 1) are factors of the expression \(Lx^{3} + 2kx^{2} + 24\), find the values of L and k.

A.

L = -6, k = -9

B.

L = -2, k = 1

C.

k = -1, L = -2

D.

L = 0, k = 1

E.

k = 0,L = 6

Correct answer is A

f(x) = Lx3 + 2kx2 + 24

f(-2) = -8L + 8k = -24

4L - 4k = 12

f(1):L + 2k = -24

L - 4k = 3

3k = -27

k = -9

L = -6

1,994.

If 0.0000152 x 0.042 = A x 108, where 1 \(\leq\) A < 10, find A and B

A.

A = 9, B = 6.38

B.

A = 6.38, B = -9

C.

A = -6.38, B = -9

D.

A = -9, B = -6.38

Correct answer is B

0.0000152 x 0.042 = A x 108

1 \(\leq\) A < 10, it means values of A includes 1 - 9

0.0000152 = 1.52 x 10-5

0.00042 = 4.2 x 10-4

1.52 x 4.2 = 6.384

10-5 x 10-4

= 10-5-4

= 10-9

= 6.38 x 10-9

A = 6.38, B = -9

1,995.

Given that cos z = L , whrere z is an acute angle, find an expression for \(\frac{\cot z - \csc z}{\sec z + \tan z}\)

A.

\(\frac{1 - L}{1 + L}\)

B.

\(\frac{L^2 \sqrt{3}}{1 + L}\)

C.

\(\frac{1 + L^3}{L^2}\)

D.

\(\frac{L(L - 1)}{1 - L + 1 \sqrt{1 - L^2}}\)

Correct answer is D

Given Cos z = L, z is an acute angle

\(\frac{\text{cot z - cosec z}}{\text{sec z + tan z}}\) = cos z

= \(\frac{\text{cos z}}{\text{sin z}}\)

cosec z = \(\frac{1}{\text{sin z}}\)

cot z - cosec z = \(\frac{\text{cos z}}{\text{sin z}}\) - \(\frac{1}{\text{sin z}}\)

cot z - cosec z = \(\frac{L - 1}{\text{sin z}}\)

sec z = \(\frac{1}{\text{cos z}}\)

tan z = \(\frac{\text{sin z}}{\text{cos z}}\)

sec z = \(\frac{1}{\text{cos z}}\) + \(\frac{\text{sin z}}{\text{cos z}}\)

= \(\frac{1}{l}\) + \(\frac{\text{sin z}}{L}\)

the original eqn. becomes

\(\frac{\text{cot z - cosec z}}{\text{sec z + tan z}}\) = \(\frac{L - \frac{1}{\text{sin z}}}{1 + sin \frac{z}{L}}\)

= \(\frac{L(L - 1)}{\text{sin z}(1 + \text{sin z})}\)

= \(\frac{L(L - 1)}{\text{sin z} + 1 - cos^2 z}\)

= sin z + 1

= 1 + \(\sqrt{1 - L^2}\)

= \(\frac{L(L - 1)}{1 - L + 1 \sqrt{1 - L^2}}\)