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WAEC Further Mathematics Past Questions & Answers - Page 27

132.

Calculate the variance of 2, (1 + 2) and (2 + 2

A.

0

B.

23

C.

23

D.

2

Correct answer is C

x (x - ˉx) (x - ˉx)

2

1 + 2

2 + 2 

-1

0

1

1

0

1

¯2

 

variance = (xˉx)2n

= 23 

133.

A force of 230N acts in its direction 065o. Find its horizontal component.

A.

208.5N

B.

197.2N

C.

118.5N

D.

97.2

Correct answer is D

Horizontal component = 230 cos 64 

= 97.2N 

134.

In what interval is the function f : x -> 2x - x2 increasing? 

A.

x = 1

B.

x < 1

C.

x > 1

D.

0 < x < 1

Correct answer is C

2x - x2 > 0

0 > x2 - 2x

x2 - 2x < 0

x(x - 2) < 0 

x > 1

135.

A function f defined by f : x -> x2 + px + q is such that f(3) = 6 and f(3) = 0. Find the value of q.

A.

-9

B.

-6

C.

15

D.

21

Correct answer is C

f(x) = x3 + px + q

f(3) 32 + 3pf + q = 6

f1(x) = 2x + p

f1(3) = 2(3) + p = 0

p = -6

from 9 + 3p + q = 6

9 + 3(-6) + q = 6

9 - 18 + q = 6

-9 + q = 6

Q = 6 + 9

= 15