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WAEC Further Mathematics Past Questions & Answers - Page 29

141.

If the binomial expansion of (1 + 3x)6 is used to evaluate (0.97)6, find the value of x. 

A.

0.03

B.

0.01

C.

-0.01

D.

-0.03

Correct answer is C

(1 + 3x )6 = (0.97)6 

1 + 3x = 0.97 

3x = 0.97.1

3x3=0.033

x = -0.01

142.

In which of the following series can be the formula S = a1r where a is the first term and r is the common ratio, be used to find the sum of all the terms? 

A.

4 + 8 + 16 + 32 + ...

B.

12 + 2 12 + 1212 + 62 12 + ..

C.

481 + 227 + 19 + 16 + ...

D.

128 + 64 + 32 + 16 + ...

Correct answer is D

No explanation has been provided for this answer.

143.

A stone was dropped from the top of a building 40m high. Find, correct to one decimal place, the time it took the stone to reach the ground. [Take g = 9.8ms2]

A.

2.9.seconds

B.

2.8 seconds

C.

2.6 seconds

D.

1.4 seconds

Correct answer is A

s = 12gt2 

40 = 12×9.8×t2

809.8=t2

t = 8.16326

t  2.9 secs

144.

Given that F = 3i - 12j, R = 7i + 5j and N = pi + qj are forces acting on a body, if the body is in equilibrium. find the values of p and q.

A.

p=-10, q=7

B.

p=-10, q=-7

C.

p=10, q=- 7

D.

p-10, q=7

Correct answer is C

If the body is in equilibrium then 

F + R = N 

3i - 12j + 7i + 5j = pi + qj

10i - 7j = pi + qj

p = 10, q = -7

145.

Find the angle between i + 5j and 5i - J

A.

0o

B.

45o

C.

60o

D.

90o

Correct answer is D

a = i + 5j and b = 5i - j

cosθ = a.b|a|.|b|

= (1×5)+(5x1)(12+52)(52+(1))2

= 5526×26 = 0

x = cos1(0), x = 90o