1 A surface has equation \(z = x \tan y\) for \(- \frac { 1 } { 2 } \pi < y < \frac { 1 } { 2 } \pi\).
- Find
- \(\frac { \partial z } { \partial x }\),
- \(\frac { \partial z } { \partial y }\).
- Find in cartesian form, the equation of the tangent plane to the surface at the point where \(x = 1\) and \(y = \frac { 1 } { 4 } \pi\).