Verify Clairaut's theorem for: \[xe^{-x^2y^2}\]
and hows this a theorem?
I think you need to understand partial derivatives before you can understand and verify clairaut's theorem, @shamil98 and I know you're not in Multivariable Calculus.
I understand partial derivatives, i've been doing calc 3 -.-
And the theorem is: \[f_{xy} (a,b) = f_{yx} (a,b)\]
Then this should be very easy. You find \(u_x,~u_y\), and then the second fixed partials, as you stated above.
Yes, it should hold true that \(\sf \color{red}{f_{xy}=f_{yx}}\)
The first derivatives are: \[f_x (x,y) =e^{-x^2y^2} - 2x^2y^2e^{-x^2y^2}\] \[f_y (x,y) = -2yx^3e^{-x^2y^2}\]
Yes, now find \(f_{xy}\) and \(f_{yx}\). You'll see that they are in fact both equal.
uh \[f_{xy} (x,y) = -2yx^2e^{-x^2y^2} - 4x^2ye^{-x^2y^2} + 4x^4y^3e^{-x^2y^2}\] \[f_{yx} (x,y) = -6x^2ye^{-x^2y^2}+4y^3x^4e^{-x^2y^2}\]
the first one simplifies to \[f_{xy} (x,y) = -6x^2ye^{-x^2y^2} + 4x^2y^3e^{-x^2y^2}\]
+4x^4****
Yessss........
kk
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