# Find equation of the tangent plane

1. Apr 22, 2011

### andrey21

Find the equation of the tangent plane to the level surface of the scalar field

$$\xi$$(x,y,z) = x2+y2+z2

at the point (1,1,2)

Looking the work through this question with someone, not to sure where to start.

2. Apr 22, 2011

### lanedance

i would start with the general equation of a plane...

the tangent plane can be thought of as a linear approximation of the function at that point