## Task Condition

Find the derivative.

$$
y=\sin ^{3}(\cos 2)-\frac{\cos ^{2} 30 x}{60 \sin 60 x}
$$
## Solution

$$
\begin{aligned}
& y^{\prime}=\left(\sin ^{3}(\cos 2)-\frac{\cos ^{2} 30 x}{60 \sin 60 x}\right)^{\prime}=0-\left(\frac{\cos ^{2} 30 x}{60 \sin 60 x}\right)^{\prime}= \\
& =-\left(\frac{\cos ^{2} 30 x}{120 \sin 30 x \cdot \cos 30 x}\right)^{\prime}=-\frac{1}{120} \cdot\left(\frac{\cos 30 x}{\sin 30 x}\right)^{\prime}= \\
& =-\frac{1}{120} \cdot(\operatorname{ctg} 30 x)^{\prime}=-\frac{1}{120} \cdot \frac{-1}{\sin ^{2} 30 x} \cdot 30=\frac{1}{4 \sin ^{2} 30 x}
\end{aligned}
$$

## Problem Kuznetsov Differentiation 9-30