In each part compute $f^{\prime}, f^{\prime \prime}, f^{\prime \prime \prime}$ and then state the formula for $f^{(n)}$
(a) $f(x)=1 / x$
(b) $f(x)=1 / x^{2}$
[Hint: The expression $(-1)^{n}$ has a value of 1 if $n$ is even and $-1$ if $n$ is odd. Use this expression in your answer.]