`\mathstrut`

Synopsis:

\mathstrut

The analogue of `\strut`

for mathematics. See `\strut`

.

The input `$\sqrt{x} + \sqrt{x^i}$`

gives output where the
second radical is taller than the first. To add extra vertical space
without any horizontal space, so that the two have the same height, use
`$\sqrt{x\mathstrut} + \sqrt{x^i\mathstrut}$`

.

The `\mathstrut`

command adds the vertical height of an open
parenthesis, `(`

, but no horizontal space. It is defined as
`\vphantom{(}`

, so see `\phantom`

& `\vphantom`

& `\hphantom`

for
more. An advantage over `\strut`

is that `\mathstrut`

adds no
depth, which is often the right thing for formulas. Using the height of
an open parenthesis is just a convention; for complete control over the
amount of space, use `\rule`

with a width of zero. See `\rule`

.