Question

If cos 9α = sinα and 9α < 90°, then the value of tan 5α is

(a) 1/√3

(b) √3

(c) 1

(d) 0

Answer 1

Answer:

(c) 1

Explanation:

Given,

cos 9α = sin α and 9α < 90°

That means , 9α is an acute angle.

cos 9α = cos(90° – α)

9α = 90° – α

9α + α = 90°

10α = 90°

α = 9°

tan 5α = tan(5 × 9°) = tan 45° = 1

Step-by-step explanation:

Answer 2

Answer:

(c) 1

hope it will help you

Step-by-step explanation: