WAEC Further Mathematics Past Questions & Answers

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1.

If \(\frac{15 - 2x}{(x+4)(x-3)}\) = \(\frac{R}{(x+4)}\) \(\frac{9}{7(x-3)}\), find the value of R

A.

\(\frac{-32}{7}\)

B.

\(\frac{-23}{7}\)

C.

\(\frac{23}{7}\)

D.

\(\frac{32}{7}\)

Correct answer is C

\(\frac{15 - 2x}{(x+4)(x-3)}\) = \(\frac{R}{(x+4)}\) + \(\frac{9}{7(x-3)}\)

 15-2x = R(x - 3) +9(x +4)/7

Put x =-4, we have 15 -2(-4) = -7R

23 -7R;

R = 23/7

2.

Given that f: x --> x\(^2\) - x + 1 is defined on the Set Q = { x : 0 ≤ x < 20, x is a multiple of 5}. find the set of range of F.

A.

{21, 91, 221}

B.

{21, 91, 221, 381}

C.

{1,21, 91, 221}

D.

{1,21, 91, 221,381}

Correct answer is A

multiples of 5 less than 20 = 5, 10 and 15

= [ 5, 10 and 15 ]x\(^2\) - x + 1


x\(^2\) - x + 1

when x = 5

5\(^2\) - 5 + 1; 25 - 5 + 1 --> 21

when x = 10

10\(^2\) - 10 + 1

100 - 9 = 91

when x = 15

15\(^2\) - 15 + 1

225 - 15 + 1 = 211

3.

Find the radius of the circle 2x\(^2\) - 4x + 2y\(^2\) - 6y -2 = 0. 

A.

17/4

B.

17/2

C.

17/√2

D.

√17/2

Correct answer is C

2x\(^3\) - 4x + 2y\(^2\) - 6y - 2 = 0

Divide through by 2: x\(^2\) - 2x + y\(^2\) -3y -1 = 0

x\(^2\) -2x + y\(^2\) - 3y = 1

x\(^2\) -2x + 1 + y\(^2\) - 3y + 9/4

= 1+ 1 + 9/4

= (x- 1)\(^2\) (y - 3/2)\(^2\)

= √[17/4]

r = √17/2 

4.

Find the value of the derivative of y = 3x\(^2\) (2x +1) with respect to x at the point x = 2. 

A.

72

B.

84

C.

96

D.

120

Correct answer is B

y 3x\(^2\) (2x +1) = 6x\(^3\) + 3x\(^2\)

dy/dx = 18x\(^2\) + 6x

At x = 2, 18(2)\(^2\) + 6(2)

= 72 + 12 = 84

5.

Find the equation of the normal to the curve y= 2x\(^2\) - 5x + 10 at P(1, 7)

A.

y+x-3 =0

B.

y-x+6=0

C.

y - x - 6=0

D.

y -x+ 3 =0

Correct answer is C

From y= 2x- 5x 10 ; dy/dx= 4x-5

But at (1, 7); m\(_1\) = (dy/dx)\(_{1,7}\)

= 4(1) - 5 = -1

Using m\(_1\)m\(_2\),= -1; m\(_2\) = 1.

Gradient m\(_2\), of normal at (1,7) is 1.

Using y - y\(_1\) = m(x - x\(_1\))

y - 7 = 1(x - 1) ;

y - 7 = x - 1

y - x - 6 = 0