We use _ to get the 'bottom' parts of summations, products, and limits, as well as the subscripts of logarithms. We use ^ to get the 'top' parts of sums and products. (Integration symbols work the same way, as you'll see in the calculus section.) Click here for a few other commands which take 'bottom' parts.

|Symbol|Command|h
|$\large \textstyle \sum_{i=1}^{\infty}\frac{1}{i}$|\\sum_{i=1}^{\\infty}\frac{1}{i}|
|$\large \textstyle \prod_{n=1}^5\frac{n}{n-1}$|\\prod_{n=1}^5\\frac{n}{n-1}|
|$\large \textstyle \lim_{x\to\infty}\frac{1}{x}$|\\lim_{x\to\infty}\\frac{1}{x}|
|$\large \textstyle \log_n n^2$|\\log_n n^2|

Some of these are prettier in display mode:
|Symbol|Command|h
|$\large \displaystyle \sum_{i=1}^{\infty}\frac{1}{i}$|\\displaystyle \\sum_{i=1}^{\\infty}\\frac{1}{i}|
|$\large \displaystyle \prod_{n=1}^5\frac{n}{n-1}$|\\displaystyle \\prod_{n=1}^5\\frac{n}{n-1}|
|$\large \displaystyle \lim_{x\to\infty}\frac{1}{x}$|\\displaystyle \\lim_{x\\to\\infty}\\frac{1}{x}|

Note that we can use sums, products, and logarithms without _ or ^ modifiers.
|Symbol|Command|h
|$\large \displaystyle \sum\frac{1}{i}$|\displaystyle\sum\frac{1}{i}|
|$\large \displaystyle \frac{n}{n-1}$|\displaystyle\frac{n}{n-1}|
|$\large \displaystyle \textstyle \log n^2$|\log n^2|
|$\large \displaystyle \textstyle \ln e$|\ln e|

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math_public
created
Sat, 05 Feb 2011 21:04:10 GMT
creator
dirkjan
modified
Sat, 05 Feb 2011 21:04:10 GMT
modifier
dirkjan
creator
dirkjan