MathCastle
Multivariable CalculusMediumChange of Variables & the Jacobian

Change of Variables & the Jacobian · Medium problem

The map x=u2−v2x = u^2 - v^2, y=2uvy = 2uv (squaring z=u+ivz = u + iv as a complex number) sends a tiny counterclockwise loop around (u,v)=(1,−1)(u,v)=(1,-1) to a tiny loop around its image. Compute the Jacobian determinant there, and state whether the image loop is traced counterclockwise or clockwise.