# 1998 - WAEC Mathematics Past Questions and Answers - page 1

Find the root of the equation 2x\(^2\) - 3x - 2 = 0

**correct option:**e

2x\(^2\) - 3x - 2 = 0

2x\(^2\) - 4x + x - 2 = 0

2x(x - 2) + 1(x - 2) = 0

(2x + 1)(x - 2) = 0

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

What value of k makes the given expression a perfect square ? m\(^2\) - 8m + k = 0

**correct option:**d

Take half the coefficient of m and square it

=> (-8/2)2 = k = 16

If log\(_{10}\) q = 2.7078, what is q?

Cos x is negative and sin x is negative.Which of the following is true of x?

^{o}< x < 90

^{o}

^{o}< x <180

^{o}

^{o}< x < 270

^{o}

^{o}< x <360

^{o}

**correct option:**c

In the 3rd quadrant, only the tan of angles are positive.

The 3rd quadrant = 180° < x < 270°

Simplify 0.63954 ÷ 0.003 giving your answer correct to two significant figures

**correct option:**d

= \(\frac{0.63954}{0.003}\)

moving the decimal places, we have

= \(\frac{639.54}{3}\)

= 213.18

\(\approxeq\) 210 (to 2 s.f.)

If log\(_{10}\) a = 4; what is a?

A student measured the length of a room and obtained the measurement of 3.99m. If the percentage error of is measurement was 5% and his own measurement was smaller than the length , what is the length of the room?

**correct option:**d

Let the actual length of the room = y m

\(\therefore \frac{y - 3.99}{y} \times 100% = 5%\)

\(100(y - 3.99) = 5y \implies 100y - 399 = 5y\)

\(100y - 5y = 399 \implies y = \frac{399}{95}\)

y = 4.2 m

When an aeroplane is 800m above the ground, its angle of elevation from a point P on the ground is 30o. How far is the plane from P by line of sight?

**correct option:**d

From the diagram, \(\sin 30 = \frac{800}{x}\)

\(x = \frac{800}{\sin 30} \)

= \(\frac{800}{0.5} \)

= 1600 m

Convert 35 to a number in base two

_{two}

_{two}

_{two}

_{two}

^{(2-n)}. Write down the first three terms of the sequence

^{3}/

_{2}, 3, 6

^{3}/

_{2}

^{3}/

_{2}, 3,

^{1}/

_{3}

^{2}/

_{3}, 3,

^{8}/

_{3}

**correct option:**b

3 x 2

^{2 - 1}= 6

3 x 2

^{2 - 2}= 3

3 x 2

^{2 - 3}=

^{3}/

_{2}