Question

$z1 = 3cis (\pi)$
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Answer 1

Explicação passo-a-passo:

$\sf z_1=3\cdot cis~(\pi)$

$\sf z_1=3\cdot(cos~\pi+i\cdot sen~\pi)$

$\sf z_1=3\cdot(-1+i\cdot0)$

$\sf z_1=3\cdot(-1+0)$

$\sf z_1=3\cdot(-1)$

$\sf \red{z_1=-3}$