229. Find the derivative of the function $y=\frac{1}{x}$.
Solution. 1 using the rule. We apply rule V1 with $\boldsymbol{u}=1, \boldsymbol{v}=\boldsymbol{x}$. Then we get

$$
y^{\prime}=\frac{0 \cdot x-1 \cdot 1}{x^{2}}=-\frac{1}{x^{2}}
$$

And the method. We first transform the given function to the form $y=\frac{1}{x}=x^{-1}$, and then apply the formula $\left(x^{n}\right)=n x^{n-1}$ :

$$
y^{\prime}=\left(x^{-1}\right)^{\prime}=-1 \cdot x^{-2}=-x^{-2}=-\frac{1}{x^{2}}
$$

230-237. Find the derivatives of the following functions: