JAMB Mathematics Past Questions & Answers - Page 214

1,066.

If cos\(\theta\) = \(\frac{a}{b}\), find 1 + tan2\(\theta\)

A.

\(\frac{b^2}{a^2}\)

B.

\(\frac{a^2}{b^2}\)

C.

\(\frac{a^2 + b^2}{b^2 - a^2}\)

D.

\(\frac{2a^2 + b^2}{a^2 + b^2}\)

Correct answer is A

cos\(\theta\) = \(\frac{a}{b}\), Sin\(\theta\) = \(\sqrt{\frac{b^2 - a^2}{a}}\)

Tan\(\theta\) = \(\sqrt{\frac{b^2 - a^2}{a^2}}\), Tan 2 = \(\sqrt{\frac{b^2 - a^2}{a^2}}\)

1 + tan2\(\theta\) = 1 + \(\frac{b^2 - a^2}{a^2}\)

= \(\frac{a^2 + b^2 - a^2}{a^2}\)

= \(\frac{b^2}{a^2}\)

1,067.

At what points does the straight line y = 2x + 1 intersect the curve y = 2x2 + 5x - 1?

A.

(-2, -3) and(\(\frac{1}{2}\), 2)

B.

(1, 0), (1, 3)

C.

(4, 0) and (0,1)

D.

(2, 0) and (0,1)

Correct answer is A

No explanation has been provided for this answer.

1,068.

If \(\frac{a}{c}\) = \(\frac{c}{d}\) = k, find the value of \(\frac{3a^2 - ac + c^2}{3b^2 - bd + d^2}\)

A.

3k2

B.

2k - k2

C.

\(\frac{3b^2k^2 - bk^2d + dk^2}{3b^2 - bd + d^2}\)

D.

k2

Correct answer is C

\(\frac{a}{c}\) = \(\frac{c}{d}\) = k

∴ \(\frac{a}{b}\) = bk

\(\frac{c}{d}\) = k

∴ c = dk

= \(\frac{3a^2 - ac + c^2}{3b^2 - bd + d^2}\)

= \(\frac{3(bk)^2 - (bk)(dk) + dk^2}{3b^2 - bd + a^2}\)

= \(\frac{3b^2k^2 - bk^2d + dk^2}{3b^2 - bd + d^2}\)

k = \(\frac{3b^2k^2 - bk^2d + dk^2}{3b^2 - bd + d^2}\)

1,069.

Find the values of x which satisfy the equation 16x - 5 x 4x + 4 = 0

A.

1 and 4

B.

-2 and 2

C.

0 and 1

D.

-1 and 0

Correct answer is C

16x - 5 x 4x + 4 = 0

(4x)2 - 5(4x) + 4 = 0

let 4x = y

y2 - 5y + 4 = 0

(y - 4)(y - 1) = 0

y = 4 or 1

4x = 4

x = 1

4x = 1

i.e. 4x = 4o, x = 0

∴ x = 1 or 0

1,070.

Make U the subject of the formula S = \(\sqrt{\frac{6}{u} - \frac{w}{2}}\)

A.

u = \(\frac{12}{2s^2}\)

B.

u = \(\frac{12}{2s+ w}\)

C.

u = \(\frac{12}{2s^2 + w}\)

D.

u = \(\frac{12}{2s^2}\) + w

Correct answer is C

S = \(\sqrt{\frac{6}{u} - \frac{w}{2}}\)

S = \(\frac{12 - uw}{2u}\)

2us2 = 12 - uw

u(2s2 + w) = 12

u = \(\frac{12}{2s^2 + w}\)