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本帖最后由 永远 于 2022-11-18 12:13 编辑
指数幂与根式互化:
\(z \ne 0\),\(a\)、\(b\)\( \in {N_ + }\)
\(z = r(\cos \theta + i\sin \theta ) = r{e^{i\theta }}\)
\({z^{\frac{b}{a}}} = \sqrt[a]{{{z^b}}} = {(\sqrt[a]{z})^b} = \sqrt[n]{r}(\cos \frac{{2k\pi + \theta }}{n} + i\sin \frac{{2k\pi + \theta }}{n}) = \sqrt[n]{r}{e^{\frac{{i(\theta + 2k\pi )}}{n}}}\),\(k = 0,1,2, \cdots n - 1.\) |
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