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20h
revised How to integrate $(x^2 - y^2) / (x^2 + y^2)^2$
added 80 characters in body
21h
asked How to integrate $(x^2 - y^2) / (x^2 + y^2)^2$
Jan
15
comment Is there any “formula” that allows us make change of variables in surface integrals?
If I may, could you give me the reference textbooks for the above?
Dec
23
comment Proof of Cauchy Riemann Equations in Polar Coordinates
I think this is a standard approach though at its present form it is not completely rigorous. But surely this can be made rigorous by applying some MVT argument along one of the lines above.
Dec
4
revised What is general relationship between Lebesgue-Stieltjes measurability and Lebesgue measurability?
added 476 characters in body
Dec
4
asked What is general relationship between Lebesgue-Stieltjes measurability and Lebesgue measurability?
Nov
21
revised If $x$ is a Lebesgue point of $f$, $f \in L^p$ and $f(x)=0$, then it is a Lebesgue point of $f^p$ where $p>1$ (finite)?
added 88 characters in body
Nov
21
asked If $x$ is a Lebesgue point of $f$, $f \in L^p$ and $f(x)=0$, then it is a Lebesgue point of $f^p$ where $p>1$ (finite)?
Nov
11
awarded  Popular Question
Nov
7
revised How does perturbation method guarantee its solution for the perturbed pde $\Delta u + \epsilon u^2 =0$
added 164 characters in body
Nov
7
comment How does perturbation method guarantee its solution for the perturbed pde $\Delta u + \epsilon u^2 =0$
I really thank for you answer. If you don't mind one further question: In 2, you said I need several theorems (especially ones in Nonlinear PDE). So where can I get those? Could you name some papers or textbooks where I can learn these theorems from?
Nov
6
revised How does perturbation method guarantee its solution for the perturbed pde $\Delta u + \epsilon u^2 =0$
deleted 456 characters in body
Nov
6
revised How does perturbation method guarantee its solution for the perturbed pde $\Delta u + \epsilon u^2 =0$
added 77 characters in body
Nov
6
asked How does perturbation method guarantee its solution for the perturbed pde $\Delta u + \epsilon u^2 =0$
Oct
20
asked Where to learn perturbation theory for pde (in introductory level)? [Reference Request]
Sep
20
awarded  Yearling
Aug
4
comment If $f(x,y,z)$ takes a maximum $f(x_0,y_0,z_0)$ under $g(x,y,z)=1$ then $\nabla f$ is parallel to $\nabla g$ at the point under any condition?
Thank you. If you don't mind, could you name me references for KKT and Lagrange multiplier methods? Since all the textbooks I have does not have sections on these topics, not even Lagrange one. Thanks. I'd prefer if the textbooks are rigorous in manner.
Aug
4
asked If $f(x,y,z)$ takes a maximum $f(x_0,y_0,z_0)$ under $g(x,y,z)=1$ then $\nabla f$ is parallel to $\nabla g$ at the point under any condition?
Jul
2
awarded  Curious
Jul
2
awarded  Inquisitive