# Math Help - Equation of Tangent Plane?

1. ## Equation of Tangent Plane?

Find the equatioon of the tangent plane of the surface

z^2+x^2-4xy+y^2=2 at point (1,1,2) do i find fx and fy then using the equation of the tangent plane?

2. This works a little different than when z = f(x,y)

you could solve for z and proceed

however there is an easier way

Use fx(1,1,2)(x-1) + fy(1,1,2)(y-1) + fz(1,1,2)(z-2) = 0

and then solve for z

3. O true I think i saw that equation later on the textbook when thier trying to talk about tangent planes to level surfaces thanks!

4. Hey also when solving for say fz fx or fy i perfrom the dervitive impicityly write? becuase z is a function of x and y correct or am i wrong?