MaxWong

I think we don't have to use any formulae.

Just observe.

$2^{-1}+2^{-2}=\frac{1}{2}+\frac{1}{4}=\frac{3}{4}$

$2^{-1}+2^{-2}+2^{-3}=\frac{1}{2}+\frac{1}{4}+\frac{1}{8}=\frac{7}{8}$

You can observe that this sum of finite geometric series = 1 - last term.

Therefore $2^{-1}+2^{-2}+......+2^{-10}=1-2^{-10}=1-\frac{1}{1024}=\frac{1023}{1024}$

LambLamb's answer is a good explanation of this phenomenon.

$x^2+0.638x-0.033495=0\\x = {-0.638 \pm \sqrt{(0.638)^2-4(1)(-0.033495)} \over 2(1)}\\ \; \;=\frac{-0.638\pm 0.541424}{2}\\ \;\;=-0.319\pm0.270712 \\\textbf{x=-0.589712 or x=-0.048288}$

 I was looking through the forum's official LaTeX post and found out that Melody has already found out the \mathbf command which can be used with the above commands while I am still using that stupid \textbf command. LOL.

But \textbf is also useful too. If you want to type text and not to use something like \; , \space.

TextBF: $\textbf {Max is so clever}$ LaTeX code: \textbf {Max is so clever}

MathBF: $\mathbf {Max\space is\space so\space clever}$ LaTeX code: \mathbf {Max\space is\space so\space clever}

You can see that TextBF need not be done spacing with \space while MathBF must have be done spacing with it.(Sorry for bad grammar I am from China)

Pros and Cons of TextBF

Pros: Spacing is easier.

Cons: Couldn't be used with math mode formulas

Pros and Cons of MathBF

Pros: Math mode formulas can be used in mathbf

Cons: Spacing takes more time

Or did the moderators and admins remove that button?

I think that [I am not a robot] button does not appear to me. 

$Area \space of \space circle = (radius)^2\times \pi$

OR

$Area \space of \space circle = \frac{(diameter)^2}{4}\times \pi$

Thx guest :D

By the way, why don't you register to be a forum member? I see you answering everywhere in the forum.

Q:Why to type \log in LaTeX?

A:If you just type log in LaTeX, it will automatically think that l, o, and g are variables, and it will automatically become italic. If you typed \log, it will be normal but not italic.

LaTeX code 'log' : $log$

LaTeX code '\log' : $\log$

Also I found out \sin , \cos, and \tan works too

LaTeX code 'sin':$sin$    

LaTeX code '\sin':$\sin$

LaTeX code 'cos':$cos$     

LaTeX code '\cos':$\cos$

LaTeX code 'tan':$tan$

LaTeX code '\tan':$\tan$