Why is this derivation of the transformation from Cartesian to polar coordinates not correct？
6843
Explain $\iint \mathrm dx\,\mathrm dy = \iint r \,\mathrm \,d\alpha\,\mathrm dr$
56319
Intuitive way to understand Polar Coordinate Gradient
102496
Derivation of the formula for the vertex of a parabola
33100
Trigonomnetric equality involving tg
108808
$x =r\cos \theta$ and $y = r\sin\theta$, determine $\frac{\partial r}{\partial x}$ and $\frac{\partial \theta}{\partial x}$
24440
Revolving Beacon confusing calculus problem
33691
Confusion about a particular differential form being exact?
92010
A mathematically illogical argument in the derivation of Hamilton's equation in Goldstein
88489
Derivation of the polarization identities?
62878
Expressing polar complex numbers in cartesian form
141937
Prove that the $\lim_{(x,y) \to (0,0)}h(x,y)$ Does not Exist using Polar Coordinates
97768
Why is $R\cos{a} = mg$ in circular motion compared and not $R = mg\cos{a}$?
90684
confusion about the laplacian in polar coordinates
90325
Why use the derivative and not the symmetric derivative?
129319
Weird "hidden answer" in $2\tan(2x)=3\text{cot}(x)$
100007
Express partial derivatives of second order (and the Laplacian) in polar coordinates
61585
Why is area of a surface of revolution integral $2\pi y~ds$? not '$dx$'?