Question

Find the value of expression $3\left[\sin ^{4}\left(\frac{\pi}{2}-\alpha\right)+\sin ^{-1}(3 \pi-\alpha)\right]-2\left[\cos ^{6}\left(3 \frac{\pi}{2}+\alpha\right)+\cos ^{6}(5 \pi-\alpha)\right]+6$.

Answer 1

$3\left[\cos ^{4} \alpha+\sin ^{4} \alpha\right]-2\left[\sin ^{6} \alpha+\cos ^{6} \alpha\right]+6$
put $\alpha=90^{\circ}$
$=3-2+6=7$