Question

Is square root 1 minus sine squared theta = cos Θ true? If so, in which quadrants does angle Θ terminate?

Answer 1

$sin^{2} \alpha + cos^{2} \alpha = 1 \\ \\ or \\ cos \ \alpha = \sqrt{1- sin^{2} \alpha }$

The sin and cosine of any angle, α is positive in first quadrant 0-90,
sine is positive in 90-180, and the cosine in fourth quadrant 270-360.

Thus, these angles follow the pattern.