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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.

106.

Differentiate the function y = 3x2(2xx2)

A.

dydx=10x5/338x2/33

B.

dydx=10x2/338x5/33

C.

dydx=10x5/338x5/33

D.

dydx=10x2/338x2/33

Correct answer is B

y = 3x2(2xx2)=x2/3(2xx2)

= 2x5/3x8/3

Now, we can differentiate the function

107.

Find the equation of straight line passing through (2, 3) and perpendicular to the line 3x + 2y + 4 = 0

A.

3y = 5x - 2

B.

y = \frac {5}{3} \times - 2

C.

None of these

D.

3y = 2x + 5

Correct answer is D

3x + 2y + 4 = 0

Rearrange:

2y = -3x - 4

Divide both sides by 2

y = \frac {-3 \times - 4}{2}

y = \frac {-3}{2} \times - 2

∴ the gradient of the line 3x + 2y + 4 = 0 is \frac {-3}{2}

If two lines are perpendicular to each other ∴ m_1 x m_2 = -1

Let m_1 = \frac {-3}{2} \therefore m_2 = \frac {-1}{m_1} = \frac {-1}{-3/2} = \frac {2}{3}

From the equation of a line which is given as m = \frac {y - y_1}{x - x_1} where (x_1, y_1) = (2,3)

\therefore \frac {2}{3} = \frac {y - 3}{x - 2}

=3(y - 3) = 2(x - 2)

=3y - 9 = 2 x -4

=3y = 2 x -4 + 9

∴ 3y = 2x + 5

108.

A coin is thrown 3 times. What is the probability that at least one head is obtained?

A.

\frac {7}{8}

B.

\frac {3}{8}

C.

None the above

D.

\frac {1}{8}

Correct answer is A

Sample space = {HHH, HHT, HTH, THH, TTH, THT, HTT, TTT}

Total number of possible outcomes = 2 x 2 x 2 = 8

favourable number of outcomes = 7

∴Pr(at least one head) = \frac {7}{8}

109.

A boat sails 8 km north from P to Q and then sails 6 km west from Q to R. Calculate the bearing of R from P. Give your answer to the nearest degree.

A.

217^o

B.

323^o

C.

037^o

D.

053^o

Correct answer is B

tan θ = \frac {opp}{adj} = \frac {RQ}{QP} = \frac {6}{8}

tan θ = 0.75

θ = tan^{-1} (0.75) = 36.87^o

∴ The bearing of R from P = 360^o - 36.87^o = 323^o (to the nearest degree)

110.

If D = \begin{bmatrix}2& -1&3\\4&1&2\\1&-3&1\\\end{bmatrix}

Find |D|

A.

16

B.

14

C.

-23

D.

-37

Correct answer is C

\begin{bmatrix}2& -1&3\\4&1&2\\1&-3&1\\\end{bmatrix}

= 2[(1 x 1) - (2 x -3)] - (-1)[(4 x 1) - (2 x 1)] + 3[(4 x -3) - (1 x 1)]

= 2(1 - (-6)) + 1(4 - 2) + 3(-12 - 1)

= 2(1 + 6) + 1(2) + 3(-13)

= 2(7) + 1(2) + 3(-13)

= 14 + 2 - 39

∴ |D| = -23