Find the volume of the solid formed by rotating the area under the curve \( y = \frac{1}{x} \) from \( x = 1 \) to \( x = 3 \) about the y-axis.

Evaluate the derivative \( y=\sinh (x) \)

\( y=\sinh (x) \)

8. \( \int_{0}^{1}(2 x+3) d x \)

solve \( \lim _{x \rightarrow 1} \frac{x-1}{\sqrt{x}-1} \)

\( \left.\begin{array}{l}\text { 4) Expand the following function into Fourier series } \\ \qquad f(x)=\left\{\begin{array}{cc}1+\frac{2 x}{\pi} & -\pi \leq x \leq \frac{-\pi}{2} \\ -\sin x & \frac{-\pi}{2} \leq x \leq 0 \\ 1-\frac{2 x}{\pi} & 0 \leq x \leq \frac{\pi}{2} \\ +\sin x & \frac{\pi}{2} \leq x \leq \pi\end{array}\right. \\ \qquad f(x)=f(x+2 \pi)\end{array}\right\} \)