TeX has `\int`

as the integral sign. Integral expressions are formed from the use of sub- and superscript, the judicious use of spacing, and simply writing out the differential. For example, a standard integral in LaTeX looks like

- \int_a^b \! f(x) \, \mathrm{d}x.

Note the use of `\mathrm `

to make a Roman "d" which distinguishes it from the product of variables *d* and *x*. Note, too, the use of \! to bring the function closer to the integral sign and the \, to push the differential farther away. Without them, the integral looks like

- \int_a^b f(x) dx,

which, although logically identical, is less legible and rankles the aesthetic sensibilities of many.

## Examples[edit | edit source]

You can also treat the integral as a sum-class symbol with the `\limit`

command. This is most useful for double and triple integrals. For example,

`\iint\limits_D \, \mathrm{d} x\,\mathrm{d} y \quad \iiint\limits_E \, \mathrm{d} x\,\mathrm{d} y\,\mathrm{d}z`

where D and E are regions that satisfy the requirements.

And let's not forget the closed path integral.

`\oint \! \nabla f \, \`

`mathrm{d}`

t = 0**Note:**To obtain double/triple/multiple integrals and cyclic integrals one must use*amsmath*and*esint*(for cyclic integrals) packages.