Question 554019
21-20i find square root of complex no.
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z = 21-20i
angle A = arcsin(-20/29) = arctan(-20/21) =~ 316.4 degs
{{{r = sqrt(21^2 + 20^2) = 29}}}
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z = 29cis(A)
sqrt(z) = sqrt(29)*cis(A/2)
= -5 + 2i