Question

(2+√15i)²
Вычислите, комплексные числа

Answer 1

$(2+\sqrt{15}i)^{2}=4+4\sqrt{15}i+15i^{2}=4+4\sqrt{15}i+15*(-1)=4+4\sqrt{15}i-15=-11+4\sqrt{15}i$

Answer 2

$\large (2+\sqrt{15}i)^2=4+4\sqrt{15}i +(\sqrt{15}i )^2=\\4+4\sqrt{15i}+15i^2=4+4\sqrt{15}i-15=\boldsymbol{-11+4\sqrt{15}i }$