Tìm {M} biểu diễn số phức z thỏa mãn z^2 + |z|^2 = 0. {M} là

* Hướng dẫn giải

Đáp án B

$$\begin{gathered} \mathrm{Đặt} \mathrm{z}=\mathrm{x}+\mathrm{yi} (\mathrm{x};\mathrm{y}\in \mathrm{ℝ}) \\ \mathrm{Ta} \mathrm{có}: {\mathrm{z}}^2+{\left|\mathrm{z}\right|}^2=0\iff {\left(\mathrm{x}+\mathrm{yi}\right)}^2+{\mathrm{x}}^2+{\mathrm{y}}^2=0 \\ \iff 2{\mathrm{x}}^2+2\mathrm{xyi}=0 \\ \iff \left\{\begin{array}{l}2{\mathrm{x}}^2=0\\ 2\mathrm{xy}=0\end{array}\iff \left\{\begin{array}{l}\mathrm{x}=0\\ \mathrm{y}\in \mathrm{ℝ}\end{array}\right.\right. \\ \mathrm{KL}: \left\{\mathrm{M}\right\} \mathrm{là} \mathrm{trục} \mathrm{Oy} \end{gathered}$$