# Gradient – A tangent plane equation for a level surface – Exercise 4382

Exercise

Find a level surface of the scalar field

$$u=\frac{x^2+y^2}{z}$$

Passing at point (2,4,10).

Calculate the tangent plane equation to the level surface at the point.

$$\frac{x^2+y^2}{z}=2$$
$$2x+4y-z=10$$