Question

If $2co{s}^{2}A-3cosA+1=0$ and one value of A is $0^{\circ }$, the other value is:

Answer 1

$2co{s}^{2}A-3cosA+1=0$
$2co{s}^{2}A-2cosA-cosA+1=0$
$2cosA(cosA-1)-1(cosA-1)=0$
$(2cosA-1)(cosA-1)=0$
Either $2cosA-1=0$ or $cosA-1=0$
$cosA=\frac{1}{2}$ or $cosA=1$
$cosA=cos60$ or $cosA=cos0$
thus, $A={60}^{\circ },0^{\circ }$