Problem:
Find the jacobian of the vector valued function $\begin{pmatrix} f(x,y,z)\\ g(x,y,z) \\ h(x,y,z)\end{pmatrix}$ where $f(x,y,z) = \frac{x}{y}$, $g(x,y,z) = \tanh (y)$, and $h(x,y,z) = \frac{x z}{y}$
Answer:
$\left(
\begin{array}{ccc}
 \frac{1}{y} & -\frac{x}{y^2} & 0 \\
 0 & \text{sech}^2(y) & 0 \\
 \frac{z}{y} & -\frac{x z}{y^2} & \frac{x}{y} \\
\end{array}
\right)$
{'source': 'AMPS', 'file': 'amps/mathematica/calculus/jacobian/38435.txt'}