Hint: Use the addition formulas for tangent

recall: and

use the double angle formula for sine2. Solve for x,

a)

Now continue

use the double angle formula for tangentb)

Now continue.

(alternatively, you could change everything to be in terms of sine and cosine here, but I think that would be more trouble than it's worth -- maybe not)

By the way, good job with the LaTex!