Решебник по алгебре и начала математического анализа 11 класс Колягин Задание 643

\[1)\ z^{2} = - 16\]

\[z = \pm \sqrt{- 16}\]

\[z = \pm 4i.\]

\[2)\ z^{2} = - 7\]

\[z = \pm \sqrt{- 7}\]

\[z = \pm i\sqrt{7}.\]

\[3)\ z^{2} + 0,36 = 0\]

\[z^{2} = - 0,36\]

\[z = \pm \sqrt{- 0,36}\]

\[z = \pm 0,6i.\]

\[4)\ 25z^{2} + 9 = 0\]

\[25z^{2} = - 9\]

\[z^{2} = - \frac{9}{25}\]

\[z = \pm \sqrt{- \frac{9}{25}}\]

\[z = \pm \frac{3}{5}i.\]

\[5)\ z^{4} - 16 = 0\]

\[z^{4} = 16\]

\[z^{2} = \pm 4\]

\[z_{1} = \pm 2;\text{\ \ \ }z_{2} = \pm 2i.\]

\[6)\ z^{4} - 81 = 0\]

\[z^{4} = 81\]

\[z^{2} = \pm 9\]

\[z_{1} = \pm 3;\text{\ \ \ }z_{2} = \pm 3i.\]