I can't get to the root of this problem: I need the second root to be the same height as the first one
$\sqrt{F} \: \sqrt{F_{x_x}}$
I know I can use \vphantom, but I don't know how.
[Tex/LaTex] The size of roots
formattingmath-modesymbols
Related Solutions
They are different because that's what \displaystyle does. It tells the compiler that it should act as if there were no text around the equation, and so it can take as much (vertical, in this case) space as it wants. The second equation is in the default style for inline formulas (achievable with the command \textstyle if needed), and as such it is typeset in a smaller way.
If you want both square roots to be the same size, you'll have to add \displaystyle at the beginning of the second $...$ block as well.
For setting the space below the root sign, provided you are using the display style (whether it is because you inserted \displaystyle or because you are in a display environment, such as equation), \vphantom has the desired effect.
\documentclass{article}
\usepackage{amsmath}
\usepackage{amssymb}
\begin{document}
In display style :
$\displaystyle\mathcal{E}(x_{0},\frac{b}{a}\cdot\sqrt{a^2-x_{0}^2})$ en $\displaystyle \mathcal{C}(x_{0},\sqrt{a^2-x_{0}^2})$.
In text style :
$\mathcal{E}(x_{0},\frac{b}{a}\cdot\sqrt{a^2-x_{0}^2})$ en $\mathcal{C}(x_{0},\sqrt{a^2-x_{0}^2})$.
Only the fraction is in display style here :
$\mathcal{E}(x_{0},{\displaystyle\frac{b}{a}}\cdot\sqrt{a^2-x_{0}^2})$ en $\mathcal{C}(x_{0},\sqrt{a^2-x_{0}^2})$.
And with \textasciibackslash vphantom :
$\displaystyle\sqrt{a^{2}-x_{{0}}^{2}}$
compared to
$\displaystyle\sqrt{\vphantom{\frac{a}{b}}a\^{2}-x_{{0}}^{2}}$
\end{document}
And an illustration of the effect of \vphantom :
A simple solution is to rotate \bigsqcup to get the missing \bigsqcap:
\documentclass[12pt]{article}
\usepackage{mathptmx}
\usepackage{graphicx}
\makeatletter
\providecommand{\bigsqcap}{%
\mathop{%
\mathpalette\@updown\bigsqcup
}%
}
\newcommand*{\@updown}[2]{%
\rotatebox[origin=c]{180}{$\m@th#1#2$}%
}
\makeatother
\begin{document}
\[\bigsqcup \bigsqcap \bigcup \bigcap\]
\[X\bigsqcup_0^\infty Y \bigsqcap_0^\infty Z\]
\[\bigsqcup\textstyle\bigsqcup
\scriptstyle\bigsqcup\scriptscriptstyle\bigsqcup\]
\[\bigsqcup\textstyle\bigsqcap
\scriptstyle\bigsqcap\scriptscriptstyle\bigsqcap\]
\end{document}
Remarks:
The rotation switches to text mode (
\hbox).\mathpaletteis the method to get the current math style that we need, when we reenter math in the rotated box for\bigsqcup. The first argument of\@updownis the math style (\displaystyle,\textstyle, …), the second argument is the unrotated symbol. Thus\@updowncan also be used for the rotation of other symbols.\m@thsuppresses\mathsurroundfor the case this value is set to avoid that space that should surround math formulas appears inside the formula.
Best Answer
Aligning square roots in the same formula requires some work if the symbols under the square root are not uniform in height and depth.
You can either add a phantom to the first square root or smash the bottom of the second one: