JAMB Mathematics Past Questions & Answers - Page 74

366.

If \(\frac{2 \sqrt{3} - \sqrt{2}}{\sqrt{3} + 2 \sqrt{2}}\) = m + n √ 6,

find the values of m and n respectively

A.

1, − 2

B.

− 2, n = 1

C.

\(\frac{-2}{5}\), 1

D.

\(\frac{2}{3}\)

Correct answer is B

\(\frac{2 \sqrt{3} - \sqrt{2}}{\sqrt{3} + 2 \sqrt{2}}\)= m + n√6

\(\frac{2 \sqrt{3} - \sqrt{2}}{\sqrt{3} + 2 \sqrt{2}}\) x \(\frac{\sqrt{3} - 2 \sqrt{2}}{\sqrt{3} - \sqrt{2}}\)


\(\frac{2 \sqrt{3} (\sqrt{3} - 2 \sqrt{2}) - \sqrt{2}(\sqrt{3} - 2 \sqrt{2})}{\sqrt{3}(\sqrt{3} - 2 \sqrt{2}) + 2 \sqrt{2}(\sqrt{3} - 2 \sqrt{2})}\)

\(\frac{2 \times 3 - 4\sqrt{6} - 6 + 2 \times 2}{3 - 2 \sqrt{6} + 2 \sqrt{6} - 4 \times 2}\)

= \(\frac{6 - 4 \sqrt{6} - \sqrt{6} + 4}{3 - 8}\)

= \(\frac{0 - 4 \sqrt{6} - 6}{5}\)

= \(\frac{10 - 5 \sqrt{6}}{5}\)

= − 2 + √6

∴ m + n\(\sqrt{6}\) = − 2 + √6

m = − 2, n = 1

367.

Simplify (3√64a3)\(^{−1}\)

A.

4a

B.

\(\frac{1}{8a}\)

C.

8a

D.

\(\frac{1}{4a}\)

Correct answer is D

(3√64a3)\(^{-1}\)

\(\frac{1}{(3√64a^3)

= \(\frac{1}{4a}\)

368.

Find the gradient of the line joining the points (3, 2) and (1, 4)

A.

3/2

B.

2/1

C.

-1

D.

3/2

Correct answer is C

Gradient of line joining points (3, 2), (1, 4)

Gradient = \(\frac{\text{Change in Y}}{\text{Change in X}}\)

= \(\frac{y_2 - Y_1}{x_2 - x_1}\)\)

(X1, Y1) = (3, 2)

(X2, Y2) = (1, 4)

Gradient = \(\frac{4 − 2}{1 + 3}\)

= \(\frac{2}{-2}\)

= −1

369.

The operation * on the set R of real number is defined by x * y = 3x + 2y − 1, find 3* − 1

A.

9

B.

- 9

C.

6

D.

- 6

Correct answer is C

x * y is an operation on 3x + 2y − 1

Find 3A − 1

x = 3, y = −1

3 * − 1 on 3x + 2y − 1

3(3) + 2(−1) −1

= 9 − 2 − 1

= 6

370.

Make S the subject of the relation
p = s + \(\frac{sm^2}{nr}\)

A.

s = \(\frac{nrp}{nr + m^2}\)

B.

s = nr + \(\frac{m^2}{mrp}\)

C.

s = \(\frac{nrp}{mr}\) + m2

D.

s = \(\frac{nrp}{nr}\) + m2

Correct answer is A

p = s + \(\frac{sm^2}{nr}\)

p = s + ( 1 + \(\frac{m^2}{nr}\))

p = s (1 + \(\frac{nr + m^2}{nr}\))

nr × p = s (nr + m2)

s = \(\frac{nrp}{nr + m^2}\)