\(\begin{array}{l}\text { b) } y=\sin ^{3} x+\cot 5 x \\ y^{\prime}=3 \sin ^{2} x(\sin x)^{\prime}-\frac{(5 x)^{\prime}}{\sin ^{2} 5 x}\end{array}\)

\(=3 \sin ^{2} x \cdot \cos x-\frac{5}{\sin ^{2} 5 x}\)