# Math Help - Equation of tangent plane

1. ## Equation of tangent plane

For (x^3)z + (z^3)x - 2yz = 0, find the equation of the tangent plane to the surface at (1,1,1). I'm not quite sure how to start this problem.

2. Originally Posted by tdat1979
For (x^3)z + (z^3)x - 2yz = 0, find the equation of the tangent plane to the surface at (1,1,1). I'm not quite sure how to start this problem.
Okay, start by finding the gradient of the function f(x,y,z)= $x^3z+ z^3x- 2yz$. That vector, evaluated at (1, 1, 1), will be perpendicular to the tangent plane.