How to avoid sub-stacks being squeezed onto the baseline?

Question

I'm using XeLaTeX on Linux (just to pre-empt any questions about that...)

I think my question is best described with this Picture:

As you can see in the red circles, the n \to \infty line got squeezed onto the baseline when \lim is used inside something like \frac{}{}, here's the relevant code portion:

    &=& \lim_{n \to \infty} - \frac{1}{n} \frac{c^{\frac{1}{n}}(c-1)}{c^{\frac{1}{n}} - 1} \\
    &=& - \frac{\lim_{n \to \infty} c^{\frac{1}{n}} (c-1)}
               {\lim_{n \to \infty} n \left(c^{\frac{1}{n}}-1\right)} \\

(the portion is inside an eqnarray* environment)

It should be evident, that in both instances, \lim has the same parameters, but behaves differently.

How do I avaid that line being squeezed over next to \lim rather than below it?

On a lesser note: I'd like to give my exponents a bit more headroom (blue circles), make them smaller maybe or something. Please advice what I should do.

Answer 1

There are three problems in your input.

1. Never use eqnarray.

2. It's better not to use fractions in exponents.

3. In this particular case, \lim\limits seems justified.

Here is an example:

\documentclass{article}
\usepackage{amsmath}

\begin{document}
\begin{align*}
&= \lim_{n \to \infty} - \frac{1}{n} \frac{c^{1/n}(c-1)}{c^{1/n} - 1} \\
&= - \frac{\lim\limits_{n \to \infty} c^{1/n} (c-1)}
          {\lim\limits_{n \to \infty} n (c^{1/n}-1)}
\end{align*}
\end{document}