Suppose x is an angle in the second quadrant such that cosx=-8/17, what is the value of tan(3x/2)?

Answer 1

first get you results to sine and cosine of x
since you are in II, from your diagram,
sinx = 15/17
tanx = -15/8

use the formula for tan(3x) you just found in your other post.

then apply the formula for tan(A/2)

actually that is a nice one:
tan (A/2) = (1 - cosA)/sinA

good luck