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Square Roots of a Complex Number (1 Viewer)

frog1944

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Hi,

In the syllabus it states that students should be able to "prove that there are always two square roots of a non-zero complex number".

How do you do this?

I haven't been able to find anywhere with a good proof and none of my textbooks have it.

Thanks
 

InteGrand

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Given any non-zero complex number r*cis(theta), it has two square roots (+/-)sqrt(r)*cis(theta/2). (These are clearly distinct if z =/= 0, i.e. r =/= 0.)
 

frog1944

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Thank you very much for that braintic, I have not seen it proved that way. Thanks InteGrand
 

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