Question

5-3cos2a если sina=-1/6

Answer 1

$sina=-\frac{1}{6} \\ \\ sin^2a=\frac{1}{36} \\ \\ 5-3cos^2a=2+3(1-cos^2a)=2+3sin^2a=2+\frac{3}{36}=2\frac{1}{12}$