sine=opp/hyp, sin30=0.5, sin45=0.707, sin60=0.866, sin90=1
cosine=adj/hyp,cos0=1, cos30=0.866, cos45=0.707, cos60=0.5
tangent=opp/hyp, tan0=0,tan30=0.577, tan45=1, tan60=1.732,tan90= ∞
http://en.wikipedia.org/wiki/Unit_circle
http://en.wikipedia.org/wiki/Trig
http://en.wikipedia.org/wiki/Exact_trigonometric_constants

http://en.wikipedia.org/wiki/Euler_formula
http://en.wikipedia.org/wiki/Euler_identity
http://en.wikipedia.org/wiki/Planck_voltage
http://en.wikipedia.org/wiki/Variables_commonly_used_in_physics