TeX - LaTeX Stack Exchange is a question and answer site for users of TeX, LaTeX, ConTeXt, and related typesetting systems. Join them; it only takes a minute:

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

I have this equation:

B_{1} = 0.9(B_{2})  + \\ 
   \sqrt{(x_{1}^2 + y_{1}^2 + z_{1}^2)}-\sqrt{(x_{2}^2 + y_{2}^2 + z_{2}^2)} 

I heard the B_{1} is some kind of result (like a sum, product, etc.) and must be declared as such, so TeX applies the math style guide - correct appearance on it.

But I dont know what it is and how to mark it. Which command can I use here?

share|improve this question
Do you mean summation? – Harish Kumar Mar 24 '12 at 8:44
up vote 4 down vote accepted

You can't have a line break in an equation environment, so the \\ does nothing.

A better way to type the equation could be

B_{1} = 0.9\,B_{2} + \Bigl[
        \sqrt{(x_{1}^2 + y_{1}^2 + z_{1}^2)}-
        \sqrt{(x_{2}^2 + y_{2}^2 + z_{2}^2)} \; \Bigr] 

so that the various components of the equation are more visible.

I've made a couple of changes:

  • \Bigl[ for the opening bracket and \Bigr] for the closing one (as \bigg size seems too much). Notice the final l or r to declare the type of delimiter;

  • a thin space \, between the decimal number 0.9 and B_{2} (which I wouldn't put in parentheses), as the result of 0.9B_{2} might be confusing;

  • a thick space between the second square root and the closing bracket for symmetry with the space at the start.

There is no special way to mark B_{1}: it's just a symbol with a subscript.

enter image description here

share|improve this answer
this is very helpful, but my prof really told me the B_{1} can´t be italic because it´s something different like the "x" which would be correct as italic. I mean it must be something like a special type of result that mathematicans wouldnt write italic. – dan Mar 24 '12 at 8:57
I don't really know: you should look in the literature in your field in order to see what's the usual form. Maybe \mathrm{B}_{1}? – egreg Mar 24 '12 at 9:05
or \mathbf{B}_{1}? – Harish Kumar Mar 24 '12 at 9:12
I will use that, thank you! I was hoping someone could tell me how you would call the "B", but I guess I should go to maths.stackexchange for that. Thank you guys! – dan Mar 24 '12 at 9:14
@dan With french notations, we need to use \usepackage[upright]{fourier}. I think some other packages for fonts have this option (upright) – Alain Matthes Mar 24 '12 at 9:14

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.