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 am LaTeX begginer and when I run this equation, I am getting the error:

! Argument \align* has an extra {. 

Here is the equation.

C_s & = \displaystyle \max_{P(g_M)} \int_0^{\infty} 
        \bigg[ \left(1-\exp\left(-\frac{g_M}{\overline{g}_W}\right) \right)
            \log\left(1+\frac{g_MP(g_M)}{N_M}\right)- \\
            \int_0^{g_M} \log\left(1+\frac{g_WP(g_W)}{N_W}\right)
        dg_W \bigg] 
        \frac{1}{\overline{g}_W}\exp\left(-\frac{g_M}{\overline{g}_M}\right) dg_M \\ 
    & = \max_{P(g_M)} \int_0^{\infty} 
        \bigg[\log \left(1+\frac{g_MP(g_M)}{N_M}\right) -
            \bigg(Ei\left(\frac{1}{\overline{g}_WP(g_M)}\right)- \\
        \frac{1}{\overline{g}_M}\exp\left(-\frac{g_M}{\overline{g}_M}\right) dg_M 

Can someone please help? Thank in advance

share|improve this question
Welcome to TeX.SX. A tip: If you indent lines by 4 spaces, then they're marked as a code sample. You can also highlight the code and click the "code" button ({}) or select your code and hit Ctrl+K. – Jubobs Mar 8 '13 at 19:15
I have edited your code to make it more legible. Why are you using multiline and align at the same time? It seems like you are missing alignment characters (ampersands &). – Corentin Mar 8 '13 at 19:30

This is probably close enough to what you are trying to achieve:



C_s & = \max_{P(g_M)} \int_0^{\infty} 
        \bigg[ \left(1-\exp\left(-\frac{g_M}{\overline{g}_W}\right) \right)
            \log\left(1+\frac{g_MP(g_M)}{N_M}\right) \\
    &\quad -\int_0^{g_M} \log\left(1+\frac{g_WP(g_W)}{N_W}\right)
        dg_W \bigg] 
        \frac{1}{\overline{g}_W}\exp\left(-\frac{g_M}{\overline{g}_M}\right) dg_M 
    & = \max_{P(g_M)} \int_0^{\infty} 
        \bigg[\log \left(1+\frac{g_MP(g_M)}{N_M}\right) 
            \bigg(Ei\left(\frac{1}{\overline{g}_WP(g_M)}\right) \\
    &\quad   -Ei\left(\frac{g_M}{\overline{g}_W}
        \frac{1}{\overline{g}_M}\exp\left(-\frac{g_M}{\overline{g}_M}\right) dg_M 


enter image description here

A couple of points:

  • It is perfectly ok to use split inside align (see for instance this question).
  • You should put the minus signs after line breaking.
  • You don't need displaystyle as equations are already displayed in the align environment.
  • You can improve the alignment by adding white space with \quad, \qquad or even \phantom.
share|improve this answer
I wouldn't even use split, no need. Just ={}& and &- – daleif Mar 8 '13 at 19:52
In this case you are right, there is no need to use split but the advantage I see in using it is that if we were using align then split would automatically take care of the tag, whereas otherwise you have to do it manually. – Corentin Mar 8 '13 at 21:38

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.