Question

What values between $0^o$ and ${360}^o$ may $A$ have when
$\cos A=\frac{1}{2}$

Answer 1

$\cos A=\frac{1}{2}$

When $A$ is in first quadrant $\angle A={60}^{\circ }$

When $A$ is in fourth quadrant $\angle A={360}^{\circ }-{60}^{\circ }={300}^{\circ }$

In second and third quadrants $\cos A=\frac{1}{2}$ will not be satisfied.$\because \cos A$ is negative in second and third quadrants.