Question

Given that cosA = -8/17  and sinA is negative, determine the value of tanA.​

Answer 1

tan A = -15/8.

Explanation:

sin^2a = 1 - cos^2A

= 1 - (-8/17)^2

= 225/289

So sin A= 15/17

tan A = sin A / cos A

= 15/17 / -8/17

= 15/-8

= -15/8.