I am not an astrophysicist, but I suggest that you, as an astrophysicist, use a mathematics engine that is a bit more robust. Might I suggest Wolfram Alpha: ht

I am not an astrophysicist, but I suggest that you, as an astrophysicist, use a mathematics engine that is a bit more robust. Might I suggest Wolfram Alpha: http://www.wolframalpha.com/input/?i=171%21 http://www.wolframalpha.com/input/?i=171%21