Recall that the Maclaurin series is just another name for the Taylor series at $x=0 .$ Each of the series in Exercises $31-34$ is the value of the Maclaurin series of a function $f(x)$ at some point. What function and what point? What is the sum of the series?
$$
\pi-\frac{\pi^{2}}{2}+\frac{\pi^{3}}{3}-\cdots+(-1)^{k-1} \frac{\pi^{k}}{k}+\cdots
$$