WAEC Further Mathematics Past Questions & Answers - Page 34

167.

Find the area between line y = x + 1 and the x-axis from x = -2 to x = 0. 

A.

5 square units

B.

4 square units

C.

2 square units

D.

1 square unit

Correct answer is C

\(\int^0_{-2} x + 1\) x\(^2 + x|^0_{-2}\)

0 - (2\(^2 - 2\))

= 2 square units

168.

Find correct to the nearest degree,5 the angle between p = 12i - 5j and q = 4i +3j

A.

59\(^o\)

B.

60\(^o\)

C.

75\(^o\)

D.

76\(^o\)

Correct answer is A

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

Cos\(\theta\) = \(\frac{48 - 15}{(\sqrt{189})(\sqrt{25})}\)

\(\theta = cos^{-1}\) (\(\frac{33}{61.28}\))

\(\theta\) = cos\(^{-1}\)0.5367

\(\theta\) = 59\(^o\)

169.

Which of the following vectors is perpendicular to \(\begin{pmatrix} -1 & 3 \end{pmatrix}\)?

A.

\(\begin{pmatrix} -3 & 1 \end{pmatrix}\)

B.

\(\begin{pmatrix} 1 & 3 \end{pmatrix}\)

C.

\(\begin{pmatrix} 1 & -3 \end{pmatrix}\)

D.

\(\begin{pmatrix} 1 & 3 \end{pmatrix}\)

Correct answer is A

No explanation has been provided for this answer.

170.

If y = (5 - x)\(^{-3}\), and \(\frac{dy}{dx}\)

A.

\(\frac{-15}{(5 - x)^4}\)

B.

\(\frac{-3}{(5 - x)^4}\)

C.

\(\frac{3}{(5 - x)^4}\)

D.

\(\frac{15}{(5 - x)^4}\)

Correct answer is C

y = (5 - x)\(^{-3}\) 

\(\frac{dy}{dx}\) = -3(5 - x)\(^{-4}\)

= \(\frac{-3}{(5 - x)^4}\)