User Long

Long

Member for 7 years, 11 months
Last seen more than a month ago

University of EST of CHINA(UESTC)

Network profile

Stats

269

reputation

reached

answers

questions

Loading…

Communities

View all

Badges

View all badges

This user doesn’t have any gold badges yet.

silver badge

Yearling

Feb 11, 2021

bronze badges

Curious

Aug 4, 2016
Commentator

Jun 2, 2016
Teacher

Aug 3, 2016

Top tags

View all tags

calculus

Score

Posts

Posts %

derivatives

Score

Posts

Posts %

linear-algebra

Score

Posts

Posts %

matrix-calculus

Score

Posts

Posts %

normed-spaces

Score

Posts

Posts %

optimization

Score

Posts

Posts %

Top posts

View all questions and answers

All Questions Answers

Score Newest

Given $\int_0^{\infty}e^{-x^2}dx = \frac{\sqrt{\pi}}{2}$, evaluate $\int_0^{\infty}e^{-a^2x^2-\frac{b^2}{x^2}}dx $

Jun 9, 2016

given $f(x)$ is continuous and $\int_0^{x^2}f(t)dt = x+sin\frac{\pi}{2}x$,solve $f(1)=?$

Jun 6, 2016

coordinate transformation from $S = \{(u,v)\}\big|0\leq u,v \leq 1\}$ to $D = \{(x,y)\big| 0\leq y\leq2;|x|\leq \frac{y^2}{4}-1 \}$

Jun 10, 2016

Why does this optimization problem have a closed form solution that resembles least squares so much?

Aug 3, 2016

why the vector derivative of $\frac{d(x^Ta)}{dx} = \frac{d(a^Tx)}{dx} = a^T$, why it's $a^T$ not $a$

Jan 5, 2016

how to understand the conditional probability point of view of linear regression?

Jun 1, 2016

gradient of trace$(ABA^TC)$ w.r.t a Matrix A.

Jun 1, 2016

If $\omega = e^{(\frac{2\pi i}{n})}$ why $1+ \omega + \omega^{2} + ... + \omega^{n-1} = 0 $? [duplicate]

May 31, 2016

Is it OK to cancel absolute value $|x|$ in such a integral $\int_{-\infty}^0\frac{1}{{|x|}^p}dx$ using $|x| = (-x)$?

Jun 9, 2016

Is $\sigma_n \|x\|_2 \leq \|Ax\|_2 \leq \sigma_1 \|x\|_2$?

Jul 31, 2016