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Exercise 2184Calculus › Multivariable calculus › Multiple integralsM1Added 3 Nov 2026

Jacobian of a nonlinear transformation

#Jacobian#nonlinear#change of variables

Statement

Show that under the change (u,v)=(x2−y2,2xy)(u,v)=(x^2-y^2,2xy), the Jacobian is 4(x2+y2)4(x^2+y^2).

Hint

Compute the 2×22\times 2 determinant of partials.

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Solution

Jacobian. det⁡(2x−2y2y2x)=4x2+4y2\det\begin{pmatrix}2x&-2y\\2y&2x\end{pmatrix}=4x^2+4y^2.

Conclusion. ∣J∣=4(x2+y2)|J|=4(x^2+y^2).