WAEC Past Questions and Answers - Page 1046

5,226.

Simplify; \(\frac{\sqrt{5} + 3}{4 - \sqrt{10}}\) 

A.

\(\frac{2}{3}\)\(\sqrt{5}\) + \(\frac{5}{6}\sqrt{2}\) + 2

B.

\(\frac{2}{3}\)\(\sqrt{5}\) + \(\frac{5}{6}\sqrt{2}\) + \(\frac{1}{2}\sqrt{10}\)

C.

\(\frac{2}{3}\)\(\sqrt{5}\) + \(\frac{5}{6}\sqrt{2}\) + \(\frac{1}{2}\sqrt{10}\) + 2

D.

\(\frac{2}{3}\)\(\sqrt{5}\) - \(\frac{5}{6}\sqrt{2}\) + \(\frac{1}{2}\sqrt{10}\) + 2

Correct answer is C

\(\frac{(\sqrt{5} + 3)(4 + \sqrt{10})}{(4 - \sqrt{10})(4 + \sqrt{10})}\)

= \(\frac{4\sqrt{5} + \sqrt{50} + 12 + 3\sqrt{10}}{4^2 - (\sqrt{10})^2}\)

= \(\frac{4\sqrt{5} + 5\sqrt{2} + 12 + 3\sqrt{10}}{16 - 10}\)

= \(\frac{4 \sqrt{5}}{6} + \frac{5 \sqrt{2}}{6} + \frac{12}{6} + \frac{3\sqrt{10}}{6}\)

= \(\frac{2}{3}\)\(\sqrt{5}\) + \(\frac{5}{6}\sqrt{2}\) + \(\frac{1}{2}\sqrt{10}\) + 2

5,227.

Given that X  : R \(\to\) R is defined by x = \(\frac{y + 1}{5 - y}\) , y \(\in\) R, find the domain of x

A.

{y : y \(\in\) R, y \(\neq\) 0}

B.

{y : y \(\in\) R, y \(\neq\) 1}

C.

{y : y \(\in\) R, y \(\neq\) 5}

D.

{y : y \(\in\) R, y \(\neq\) 7}

Correct answer is C

No explanation has been provided for this answer.

5,228.

If  \(\begin{pmatrix} p+q & 1\\ 0 & p-q \end {pmatrix}\) = \(\begin{pmatrix} 2 & 1 \\ 0 & 8 \end{pmatrix}\)

Find the values of p and q

A.

p = 5, q = 3

B.

p = 5, q = -3

C.

p = -5, q = -3

D.

p = -5, q = 3

Correct answer is B

p + q = 2

p - q = 8

\(\overline{\frac{2p}{2} = \frac{10}{2}}\)

p = 5

from p + q = 2

5 + q = 2

q = 2 - 5 

= -3

5,229.

If \(\int^3_0(px^2 + 16)dx\) = 129. Find the value of p

A.

9

B.

8

C.

7

D.

6

Correct answer is A

\(\int^3_0(px^2 + 16)\) = 129

\(\frac{px^2 + 1}{0 + 1} + 16x|^3_0 = 129\)

\(\frac{px^3}{3} + 16x|^3_0 = 129\)

(\(\frac{p(3)^3}{3} + 16(3)\)) - 0 = 129

9p + 48 = 129

9p = 129 - 48 

\(\frac{9p}{9} = \frac{81}{9}\) 

p = 9

5,230.

If cos x = -0.7133, find the values of x between 0\(^o\) and 360\(^o\) 

A.

44.5\(^o\) , 224.5\(^o\)

B.

123.5\(^o\) , 190.5\(^o\)

C.

135.5\(^o\) , 213.5\(^o\)

D.

135.5\(^o\) , 224.5\(^o\)

Correct answer is D

cos x = -0.7133

x = cos \(^{-1}\)(0.7133) 

= 44.496\(^o\) 

x = 180 - 44.495\(^o\) 

x = 135.5\(^o\)

and x = 180\(^o\)  + 44.495\(^o\) 

= 224.5\(^o\)