Question

URGENT! When we solve (cos²x - 1 = 0) by adding and taking the square root, how come we get the same answer when we factor (cos²x - 1) and use the zero product property to find the solution?

Answer 1

It is the same answer because you still have the same x-1 and he exponent of 2. It doesn't matter about the zero unless you are trying to find the angle of a triangle.

Explanation: