# Quod Erat Demonstrandum

## 2007/08/19

### Practice

Filed under: Uncategorized — johnmayhk @ 1:42 下午

$A\subseteq B\: \wedge\:B\subseteq A\:\Rightarrow\:A=B$

Many many people used LaTeX many many years ago. At the beginning, typing with LaTeX is quite difficult, I’m used to use Equation Editor in WORD. However, it is a very beginning (too old to start), I think it is worthy trying here.

$-2$

$V_{y=k}=\pi\displaystyle \int_a^b(f(x)-k)^2dx$

$V_{x=k}=\pi\displaystyle \int_a^b(f(y)-k)^2dy$

## 12 則迴響 »

1. Can we type with LaTeX in comment?

Try.

$A\subset B$

迴響 由 johnmayhk — 2007/08/19 @ 2:07 下午 | 回應

2. Quite good!

$3^3 + 4^3 + 5^3 = 6^3$

迴響 由 johnmayhk — 2007/08/19 @ 2:10 下午 | 回應

3. $\lim_{x\rightarrow 0} \frac{\sin x}{x} = 1$

Why? The $x\rightarrow 0$ is not under $\lim$ directly?

迴響 由 johnmayhk — 2007/08/19 @ 2:45 下午 | 回應

4. $\left(\begin{array}{rcl}\alpha&\beta&\gamma\\\delta&\epsilon&\zeta\\\eta&\theta&\iota\\\end{array}\right)$
Oh! Don’t use “enter" to make the ‘good-looking’ presentation, we need ‘ONE-LINE’ to type Latex.

迴響 由 johnmayhk — 2007/08/19 @ 2:55 下午 | 回應

5. $x_1^{\frac{1}{2}} \:is\:OK.$

迴響 由 johnmayhk — 2007/08/19 @ 10:39 下午 | 回應

6. Oops, we can use a little bit html in giving comments.

Impossible ar!

迴響 由 johnmayhk — 2007/08/22 @ 12:27 上午 | 回應

7. Compare $\int_0^1f(x)dx$ with $\int_0^1 f(x)dx$

$\frac{\pi}{4} = 1 - \frac{1}{3} + \frac{1}{5} - \frac{1}{7} + \frac{1}{9} - \dots$

迴響 由 johnmayhk — 2007/10/28 @ 2:37 下午 | 回應

8. Compare $\int_0^1 f(x)dx$ with $\int_0^1 f(x)dx$

迴響 由 johnmayhk — 2007/10/28 @ 2:41 下午 | 回應

9. Comment #7

Add the following just in front of the second dollar sign

&bg=ffffff&fg=000000&s=1

Comment #8

Only

&bg=ffffff&fg=000000

So, to make darker formula, use size = 1, i.e. in comment #7

迴響 由 johnmayhk — 2007/10/28 @ 2:42 下午 | 回應

10. $\begin{pmatrix} 3 & -1 \\ 1 & 1 \end{pmatrix}$

迴響 由 johnmayhk — 2007/12/14 @ 11:49 上午 | 回應

11. $\mathbb{Q}$
$\mathbb{C}$
$\mathbb{R}$
$\mathfrak{C}$
$\mathbb{N}$
$\mathbb{Z}$

$\mathfrak{D}$
$\mathfrak{R}$
$\mathfrak{P}$
$\mathfrak{E}$
$\mathfrak{F}$

$\mathcal{D}$
$\mathcal{R}$
$\mathcal{P}$
$\mathcal{E}$
$\mathcal{F}$

迴響 由 johnmayhk — 2008/01/05 @ 5:03 下午 | 回應

12. online latex
http://mathb.in/138068

迴響 由 johnmayhk — 2017/04/25 @ 9:28 下午 | 回應