Complex number

In mathematics, the complex numbers are an extension of the real numbers by the inclusion of the imaginary unit i, satisfying i^2 = -1. Every complex number can be written in the form x+iy, where x and y are real numbers called the real part and the imaginary part of the complex number, respectively. Pairs of complex numbers can be added, subtracted, multiplied, and divided in a manner similar to that of real numbers. Formally, one says that the set of all complex numbers forms a field.

r_1 r_2 e^{i(phi_1 + phi_2)} ,

and that

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:rac{r_1 e^{iphi_1}}

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