Math & Science ⇒ I hate radicals in LaTeX !

[Cham]

I'm having troubles with an index and an exponent under a radical, and I don't know anymore what to do !

Here's a MWE to show the problem :

Code: Select all

\documentclass[12pt,letterpaper,twoside]{book}
\usepackage{lmodern}
\usepackage{amsmath}
\usepackage{tensor}

\begin{document}
	\begin{equation}
		I =
		\begin{cases}
			\, \displaystyle{\frac{1}{2} \; A \smash{\left( \tensor{t}{_0} + \alpha - \frac{\beta}{\displaystyle{\sqrt{2 \alpha \, \smash{\tensor{t}{_0} + t_0^2}}}} \, \right)}}, &\text{if $k = - 1$.} \\[18pt]
			\, \displaystyle{\frac{2}{3} \; A \, \tensor{t}{_0}}, &\text{if $k = 0$.} \\[18pt]
			\, \displaystyle{\frac{1}{2} \; A \smash{\left( \tensor{t}{_0} - \alpha + \frac{\beta}{\displaystyle{\sqrt{2 \alpha \, \tensor{t}{_0} - t_0^2}}} \, \right)}}, &\text{if $k = + 1$.}
		\end{cases}
	\end{equation}
\end{document}

Here's a preview of what it does :

radical.jpg (25.48 KiB) Viewed 4267 times

Now, the first radical has a proper size, since I smashed the "0" index, but then the "2" exponent is too close to the horizontal bar. The second radical is too big and there is too much space inside, while the "2" exponent is right.

Take note that smashing each "0" index separately doesn't change anything.

How can I lower the "2" exponent in the first line ?

[Cham]

Ah ! Removing the \displaystyle{} around the radical and adding \vphantom{1^1} inside seems to fix the problem.

Is there a better way in doing this ?