CAS: force latex to write unevaluated expression?

[Arno K]

As I currently am looking inside Latex a little bit, I stumbled upon writing a comment here using nice looking format and the prime refused to give me \[\int_a^1 \! \frac{1}{x^{n}} \, \mathrm{d}x\] instead it evaluated the integral. Is there a possibility to make it provide the integral without evaluation, perhaps a second parameter of the latex command (0:evaluate, may be default value and 1: don't)?
Arno