What is Euler's law?

Answer 1

e^(i*x) = cos(x) + i*sin(x) This is used alot in engineering. But it also has functional uses as: cos(x)= Re( e^(i*x)) = (e^(i*x) + e^(-i*x)) / 2 sin(x)= Im( e^(i*x)) = (e^(i*x) - e^(-i*x)) / 2