The angle a lies in Quadrant4, and tan (pi - 2a) = -13/12. Find the value of tan a.

Solution:

We use these formulas tan (pi - b) = - tan b and tan 2a = 2 tan a/(1 + tan^{2}a). By apply these formulas, we get one variable second degree equation of tan a. It has two solutions, one is tan a = 0.44
and the other is tan a = -2.28. Because the angle a lies in Quadrant4, so the value of tan a is negative. So, the solution is tan a = -2.28. For a detailed solution, please watch the video.