# How to type formula in tex at PF? (1 Viewer)

### Users Who Are Viewing This Thread (Users: 0, Guests: 1)

#### Dale12

I used "search" by typing "tex" but only find a thread, it seems to said that by using $$...$$ , you can type formula well.
So I tried this and preview the post, but it was not valid, and I was confused.
I just typed like below,thx:

$$\nabla(\bf{x}\cdot \bf{a})=\bf{a}+\bf{x}(\nabla\cdot\bf{a})+i(\bf{L}\times\bf{a}) \ \ where \ \ \bf{L}={\frac{1}{i}}(\bf{x}\times\nabla)$$

Last edited:

#### Moonbear

Staff Emeritus
Gold Member
Here's a thread where you can view other people's code and try your own (you're allowed to just practice using LaTex in it). It's a sticky thread in the General Physics forum in case you don't bookmark it and need to find it again later.

#### Dale12

Moonbear said:
Here's a thread where you can view other people's code and try your own (you're allowed to just practice using LaTex in it). It's a sticky thread in the General Physics forum in case you don't bookmark it and need to find it again later.

thanks, I just found it^_^. and before this, I found formula I type can be shown normally, it's glad to see this. but still there are two question:
1. it says that we use tex & /tex, but how to add [] in the beginning and the end to tell others or just show this as explanation , because they disapper as tags after u post them.
2. how to begin a second paragraph or how to type enter in formula here? I tried to insert "\\" before "where" above but failed.

Last edited:

#### Dale12

IC, thanks anyway!
1.Just add several spaces as [ tex ]...[ /tex ] .
2.add two [ tex ]...[ /tex ] can print as an "enter",maybe like below:

$$\nabla(\bf{x}\cdot\bf{a})=\bf{a}+\bf{x}(\nabla\cdot\bf{a})+i(\bf{L}\times\bf{a})$$
where
$$\bf{L}={\frac{1}{i}}(\bf{x}\times\nabla)$$

Last edited:

#### Tom Mattson

Staff Emeritus
Gold Member
There's also another set of tags: [ itex ](stuff)[ /itex ]. The "i" stands for "inline", and it does just that: It lines the TeX up with the rest of your text. Check it out.

With [ tex ] tags:

The Lorentz factor in natural units is $$\gamma=\frac{1}{\sqrt{1-v^2}}$$.

And with [ itex ] tags:

The Lorentz factor in natural units is $\gamma=\frac{1}{\sqrt{1-v^2}}$.

Gold Member

Homework Helper

#### Tom Mattson

Staff Emeritus
Gold Member
Lisa! said:
Why don't you make that a sticky thread in HW part too!?
Yeah, then it can get ignored right along with the other sticky that's there (the one that says, "Read this before posting.")

Eh, maybe I'll make my own sticky that has the most commonly used equations in basic physics.

#### Lisa!

Gold Member
Tom Mattson said:
Yeah, then it can get ignored right along with the other sticky that's there (the one that says, "Read this before posting.")

Eh, maybe I'll make my own sticky that has the most commonly used equations in basic physics.

You know Tom, you're too nice with kids in HW part. Whenever you see they don't use LaTex, you can simply post that sticky to them and ask them to learn how to use it. If you ask other HW helpers to do the same, you might be able to tackle this problem.

(Sometimes I think Greg should make a quiz about forum rules and using LaTex, and ask people to take it before registration. So only those people who can pass the test, would be allowed to post here! But I'm afraid they even don't get that they have to pass the test if they want to become a member here! :uhh:)

### The Physics Forums Way

We Value Quality
• Topics based on mainstream science
• Proper English grammar and spelling
We Value Civility
• Positive and compassionate attitudes
• Patience while debating
We Value Productivity
• Disciplined to remain on-topic
• Recognition of own weaknesses
• Solo and co-op problem solving