how do I show that:(adsbygoogle = window.adsbygoogle || []).push({});

|y + x|^2 = |y|^2 + |x|^2 + 2|yx|cos(a1-a2)

where y = |y|exp(ia1)

and

where x = |x|exp(ia2)

and how do I show that |exp(z)| = exp(Re(z)) where Re is the real part of an imaginary number z.

thanks is advance

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# Complex numbers help

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