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WAEC Further Mathematics Past Questions & Answers - Page 7

31.

A particle began to move at 27ms1 along a straight line with constant retardation of 9ms2. Calculate the time it took the particle to come to a stop

A.

3 sec

B.

2 sec

C.

4 sec

D.

1 sec

Correct answer is A

u=27ms1;a=9ms2;v=0;t=?

v=u+at;t=vua

t=0279=279

32.

Given that M is the midpoint of T (2, 4) and Q (-8, 6), find the length of MQ .

A.

√26 units

B.

√28 units

C.

√24 units

D.

√30 units

Correct answer is A

|MQ| = \frac{1}{2} |TQ|

|TQ| = √((y2 - y1)^2 + (x2 - x1)^2)

|TQ| = √((6 - 4)^2 + (-8 - 2)^2)

|TQ| = √(2^2 + (-10)^2)

|TQ| = √(4 + 100) = √104

|TQ| = 2√26 units

|MQ| = \frac{1}{2} |TQ| = 2 \times 2√26

|MQ| = √26 units

33.

Find the radius of the circle 2x^2 + 2y^2 - 4x + 5y + 1 = 0

A.

\frac{\sqrt33}{4}

B.

\frac{\sqrt5}{6}

C.

\frac{5}{6}

D.

\frac{33}{4}

Correct answer is A

Standard Form equation of a circle (Center-Radius Form): (x − a)^2 + (y − b)^2 = r^2

Where "a" and "b" are the coordinates of the center and "r" is the radius of the circle

2x^2+2y^2-4x+5y+1=0

Divide through by 2

= x^2+y^2-2x+\frac{5}{2}y+\frac{1}{2}= 0

=x^2-2x+y^2+\frac{5}{ 2}y=-\frac{1}{ 2}

=x^2-2x+1^2+y^2+\frac{5}{ 2}y+(\frac{5}{ 4})^2-1-\frac{25}{16}=-\frac{1}{2}

=(x-1)^2+(y+\frac{5}{4})^2=-\frac{1}{2}+1+\frac{25}{16}

=(x-1)^2+(y-(-\frac{5}{4}))^2=\frac{33}{16}

=(x-1)^2+(y-(-\frac{5}{4}))^2=(\frac{\sqrt33}{4})^2

\therefore a = 1, b = - \frac{5}{4} and r \frac{\sqrt33}{4} (answer)

34.

The table shows the operation * on the set {x, y, z, w}.

* X Y Z W
X Y Z X W
Y Z W Y X
Z X Y Z W
W W X W Z

Find the identity of the element.

A.

W

B.

Y

C.

Z

D.

X

Correct answer is C

From the table, x * z = x, y * z = y, z * z = z and w * z = w

∴ z is the identity element

35.

If(\frac{1}{9})^{2x-1} = (\frac{1}{81})^{2-3x}find the value of x

A.

-\frac{5}{8}

B.

-\frac{3}{4}

C.

\frac{3}{4}

D.

-\frac{5}{8}

Correct answer is D

(\frac{1}{9})^{2x-1} = (\frac{1}{81})^{2-3x}

(\frac{1}{9})^{2x-1} = (\frac{1}{9})^{2(2-3x)}

(\frac{1}{9})^{2x-1} = (\frac{1}{9})^{4-6x}

Since the bases are equal, powers can be equated

= 2x - 1 = 4 - 6x

= 2x + 6x = 4 + 1

= 8x = 5

\therefore x = \frac{5}{8}