# Math Help - Implicit Differentiation - I'm stuck

1. ## Implicit Differentiation - I'm stuck

The question is "Use implicit differentiation to write the equation of the tangent line to the graph at the specified point"

I'm given (x^2) - (2xy) + (y^2) - (2x) - (2y) + 1 = 0 with (2,3+2sqrt(2))

I tried to differentiate by the way I know getting 2x - (2xy' + 2y) + 2yy' - 2 - 2y' = 0 which simplies to (x-y-1)/(x-y+1) = y'

So I'm stuck here, is this it? am I done with the problem? I don't know why they gave me (2,3+2sqrt(2))

Can anyone help me please... I'm stuck..

Thank you

2. ## Re: Implicit Differentiation - I'm stuck

It goes through the point $(2, 3 + 2 \sqrt{2})$, so to evaluate y' at that point, substitute $x = 2$ and $y = 3 + 2 \sqrt{2}$. This will give you the slope of the tangent line. You know that it goes through that point, so you can find the equation of the tangent line.

3. ## Re: Implicit Differentiation - I'm stuck

Thank you so much!!!!!!!!