# Thread: Solving a trig equation

1. ## Solving a trig equation

If possible, find the exact solutions algebraically

(sin2x + cos2x)^2 =1

2. Originally Posted by >_<SHY_GUY>_<

If possible, find the exact solutions algebraically

(sin2x + cos2x)^2 =1
Expand the left hand side and apply the Pythagorean Identity. After simplifying, the equation becomes $\displaystyle 2 \sin (2x) \cos (2x) = 0$ which can be easily solved in a number of ways.

3. Originally Posted by >_<SHY_GUY>_<
$\displaystyle (\sin{u} +\cos{u})^2 =1$