Question

Find the other value of A if one value of A is ${60}^o$ and $(\sin A-1)(2\cos A-1)=0$.

Answer 1

$(\sin A-1)(2\cos A-1)=0$
Then,either $\sin A-1=0$ or $2\cos A-1=0$
$\sin A=1$ or $\cos A=\frac{1}{2}$
$A={90}^{\circ }$ or $A={60}^{\circ }$