How do I prove this identity involving polar coordinates and $\nabla$?
140024
How to obtain the gradient in polar coordinates
77951
Dirac's delta in 3 dimensions: proof of $\nabla^2(\|\boldsymbol{x}-\boldsymbol{x}_0\|^{-1})=-4\pi\delta(\boldsymbol{x}-\boldsymbol{x}_0)$
153158
how to get $dx\; dy=r\;dr\;d\theta$
40549
How to proof the the derivative of $x^2$ is $2x$?
41191
How to prove this $\pi$ formula?
86193
Rigorous proof that $dx dy=r\ dr\ d\theta$
59409
Show Laplace operator is rotationally invariant
11711
Prove trigonometry identity for $\cos A+\cos B+\cos C$
14491
Verify the following relationship: $\nabla \cdot (a \times b) = b \cdot \nabla \times a - a \cdot \nabla \times b $
76510
vector identity for triple scalar product
71708
Proving that $\left( \frac{\partial^2}{\partial x^2} + \frac{\partial^2}{\partial y^2} \right) \lvert f(z) \rvert^2 = 4 \lvert f'(z) \rvert^2$
147886
Proof of the angle sum identity for $\sin$
102730
Is my proof correct? (Conformal equivalence of two circular annuli)
16443
Laplacian in polar coordinates
120841
Solving the Helmholtz equation in polar coordinates
24585
Proving that $\mathbf{W}$+$\mathbf{W^{\perp}}$=$\mathbb{R^{n}}$
83853
Prove that the polar decomposition of normal matrices, $A=SU$, is such that $SU=US$