Find all solutions for each of the following equations in the intervals given:

a)$\displaystyle sin^2x = \frac{1}{4}, \frac{\pi}{2}<=x<2\pi; $

b)$\displaystyle tan^2x = 1, {-\pi}<=x<\pi; $

how would i attack these questions? if you could explain i would really appreciate it. thank u