Home Page	MEI Courses	Registration	Workshops & Consulting	Courseware Archive & Consulting	Guestbook

Euler's Formula and Trig Identities

e^iu = cos(u) + i sin(u).

Here's a way to use it

e^{i( u+v )} = cos( u+v ) + i sin( u+v ) =

e^iu e^iv = (cos(u) + i sin(u)) (cos(v) + i sin(v)) =

( cos(u) cos(v) - sin(u) sin(v) ) + i ( cos(u) sin(v) + cos(v) sin(u) ).

Match up those real and imaginary parts to get a pair of really important trig identities.