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10h
revised Prove the following property of simple functions
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2d
answered Proving that $f^2$ is differentiable given that f is differentiable at $(x_0,y_0)$
2d
reviewed Approve Proving that $f^2$ is differentiable given that f is differentiable at $(x_0,y_0)$
2d
answered Property of real functions when derivative approaches zero
Feb
7
answered Using definition of derivative to prove that $\lim_{h \to 0} \dfrac{f(x_0+bh)-f(x_0-ch)}{(b+c)h}=f'(x_0) $
Feb
7
revised If $u \in W^{1,p}(I) \bigcap C_c(I)$ then $u \in W_{0}^{1,p}(I) $ where $ W^{1,p}(I)$ is the Sobolev Space
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Feb
7
comment Show that $\lim_{z \to 0} \frac{\Re(z)}{z}$ doesn't exist.
It looks fine. Anyway, it would suffice to approach $0 \in \mathbb{C}$ first along $\mathbb{R}$ and then along $i\mathbb{R}$.
Feb
7
revised Is $f( x + iy) = e^{-x} e^{-iy}$ complex - differentiable?
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Feb
7
answered Is $f( x + iy) = e^{-x} e^{-iy}$ complex - differentiable?
Feb
7
answered $\lim_{(x,y)\to(0,0)}\frac{x^2y^2}{\sin(x)\cos(y)}$ is this done correctly?
Feb
7
revised $\lim_{(x,y)\to(0,0)}\frac{x^2y^2}{\sin(x)\cos(y)}$ is this done correctly?
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Feb
4
revised differentiability of a function
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Feb
3
revised Help evaluating the integral of $\frac{1}{1+\sqrt{1-x^2}}$ over $[0,1]$
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Feb
2
comment Show that $\lim_{x \to x_0} f(x)$ exist
(3) Because the limit is always unique (in a Hausdorff space). Hence you must be sure that different sequences do not lead you to different limits.
Jan
31
comment Prove that $(e^x-\ln y)^2+(x-y)^2\geq 2$
Why do you believe that you can solve it without calculus of several variables?
Jan
15
comment If $f\in L^2$ then there is $g$ continuous with compact support s.t. $\int (f-g)^2<\varepsilon$
You need to prove that $C_c$ is dense in $L^2$. I am unsure if you can deduce this from the density in $L^1$.
Jan
14
answered $(f_n)$ in $L^p(\Omega)$ satisfying $f_n(x) \to f(x)$ a.e. and $\|f_n\|_p \to \|f\|_p$, then $\|f_n - f\|_p \to 0$?
Jan
12
comment What does “proportional” mean?
I guess the standard use of the proportionality symbol requires $b=0$.
Jan
7
answered Exponential growth as check for integrability
Jan
7
revised Is $|9x-1|^3$ differentiable at $1/9$?
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