## Task Condition

Find the derivative.

$$
y=\sin \sqrt[3]{\operatorname{tg} 2}-\frac{\cos ^{2} 28 x}{56 \sin 56 x}
$$
## Solution

$$
\begin{aligned}
& y^{\prime}=\left(\sin \sqrt[3]{\tan 2}-\frac{\cos ^{2} 28 x}{56 \sin 56 x}\right)^{\prime}=0-\left(\frac{\cos ^{2} 28 x}{56 \sin 56 x}\right)^{\prime}= \\
& =-\left(\frac{\cos ^{2} 28 x}{112 \sin 28 x \cdot \cos 28 x}\right)^{\prime}=-\left(\frac{\cos 28 x}{112 \sin 28 x}\right)^{\prime}= \\
& =-\frac{1}{112} \cdot(\cot 28 x)^{\prime}=-\frac{1}{112} \cdot \frac{-1}{\sin ^{2} 28 x} \cdot 28= \\
& =\frac{1}{4 \sin ^{2} 28 x}
\end{aligned}
$$

Problem Kuznetsov Differentiation 9-28