Complex Representation?

Question

Why we use complex representation for periodic wave?

Exp(-jwt)=cos(wt)-jsin(wt)

we just need the real part? The imaginary part is what for?

Answer 1

You need both parts, since the complex representation includes magnitude and phase. While an isolated periodic wave can be considered at zero phase, if it is to be combined with other waves, the phase relationship must be included. The magnitude of the wave is not just the real part, it is the square root of the sum of the squares of the real and imaginary parts. If two waves are added together, you add the real and imaginary parts of each to get the real and imaginary part of the combination.

Answer 2

in most cases complex equations are used to identify the position of the point in question.
j^2=-1

hence evalutating it will give us an idea of the formation of the wave.

Answer 3

iit is easier to work with the exp than with cos , if you dont need the imaginary part then just ignore it.