JAMB Mathematics Past Questions & Answers - Page 192

956.

If sin \(\theta\) = \(\frac{x}{y}\) and 0o < 90o then find \(\frac{1}{tan\theta}\)

A.

\(\frac{x}{\sqrt{y^2 - x^2}}\)

B.

\(\frac{y}{x}\)

C.

\(\frac{\sqrt{y^2 + x^2}}{y^2 - x^2}\)

D.

\(\frac{y^2 - x^2}{x}\)

Correct answer is D

\(\frac{1}{tan\theta}\) = \(\frac{cos\theta}{sin\theta}\)

sin\(\theta\) = \(\frac{x}{y}\)

cos\(\theta\) = \(\frac{\sqrt{y^2 - x^2}}{y}\)

957.

The larger value of y for which (y - 1)2 = 4y - 7 is

A.

2

B.

4

C.

6

D.

7

E.

8

Correct answer is B

(y - 1)2 = 4y - 7

y2 - 2xy + 1 = 4y - 7

y2 - 6y + 8 = 0

(y - 4)(y - 2)

y = 4 or 2 = 4

958.

Two fair dice are rolled. What is the probability that both show up the same number of points.

A.

\(\frac{1}{36}\)

B.

\(\frac{7}{36}\)

C.

\(\frac{1}{2}\)

D.

\(\frac{1}{3}\)

E.

\(\frac{1}{6}\)

Correct answer is E

A dice has 6 faces, 2 dice has 6 x 6 = 36 combined face

Prob. of both showing the same number of points

= \(\frac{6}{36}\)

= \(\frac{1}{6}\)

959.

A right circular cone has a base radius r cm and a vertical angle 2yo. The height of the cone is

A.

r tan yo cm

B.

r sin yo cm

C.

r cot yo cm

D.

r cos yo cm

E.

r cosec yo cm

Correct answer is C

\(\frac{r}{h}\) = tan yo

h = \(\frac{r}{tan y^o}\)

= r cot yo