162 reputation
7
bio website
location
age
visits member for 1 year, 9 months
seen Mar 25 at 15:32

Jul
2
awarded  Curious
Dec
7
comment calculate double integral on quadrangle domain by changing of variables
I know you divide domain to small domains. But I want to calculate double integral which not need to divide. How can you do it?, or we have no any way to do it.
Dec
7
asked calculate double integral on quadrangle domain by changing of variables
Oct
23
awarded  Tumbleweed
Oct
16
asked frechet differentiable implies uniformly continuous/ absolutely continuous?
Oct
8
comment continuous implies frechet differentiable?
let $f(x)=|x|$ then $f$ is continuous at $0$, but not differentiable. Ok
Oct
7
asked continuous implies frechet differentiable?
Oct
5
accepted show that function is convex
Oct
5
comment show that function is convex
what happen if we define $+\infty -\infty =+\infty$
Oct
5
comment show that function is convex
define $+\infty -\infty =0$
Oct
5
asked show that function is convex
Sep
18
comment Show that $A$ is convex set
I started by definition of convex set: $(x_1,x_2),(y_1,y_2)\in A$ then $(\lambda x_1+(1-\lambda)y_1,\lambda x_2 +(1-\lambda)y_2)\in A$. But I don't abtain anything. Can anyone help me?
Sep
18
asked Show that $A$ is convex set
Aug
22
comment Property of $W_0^{1,p}(\Omega)$
Because $W_{0}^{1,p}\left(\Omega\right)=\overline{C_{0}^{\infty}\left(\Omega\right)}$ so we have $u_k \in C_{0}^{\infty}\left(\Omega\right)$ and $u_k$ converge to $u$ in $W^{1,p}\left(\Omega\right)$. But why $|u_k|$ has compact support. I don't understand "compact support". Can you explain more?
Aug
21
asked Property of $W_0^{1,p}(\Omega)$
Jun
22
comment separation of quotient space
Can you give me a proof or material that I can read?
Jun
22
comment check coercive in Lax-Milgram
Yes. If "+" then so easy to prove
Jun
22
comment separation of quotient space
oh, sorry. From $X/\sim$ is $T_1$ iff $[x]$ is closed in $X/\sim$, then $p^{-1}([x])$ is closed in $X$
Jun
21
comment separation of quotient space
but it isn't obvious
Jun
21
comment separation of quotient space
$[x]$ is closed in $X/\sim$ by its Hausdorff. If $p$ is quotient map. Then $[x]$ is closed in $X/\sim$ iff $p^{-1}([x])$ is closed in $X$