#1 add trig functions

[Brian Fegler]

currently, no trig functions are implemented.

I wanted to add them once I had a clean solution for
preserving the "infinitly large/infinitly precise" part
of this application with division and fractions.

[Brian Fegler]

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implemented the following:

sin, cos, tan

csc, sec, cot

need to implement arcsin, arccos, ...