复变函数求实部

来源:学生作业帮助网 编辑:作业帮 时间:2024/05/02 11:37:37
复变函数求实部

复变函数求实部
复变函数求实部

复变函数求实部
(1+√3i)/(1-√3i)= (-2+2√3i)/4
|(-2+2√3i)/4| = 1
arg((-2+2√3i)/4) = arctan (-√3) =2π/3
(-2+2√3i)/4 = cos(2π/3) + isin(2π/3)
[(1+√3i)/(1-√3i)]^10
=[(-2+2√3i)/4]^10
=[cos(2π/3) + isin(2π/3)]^10
=cos(20π/3) + isin(20π/3)
=cos(2π/3) + isin(2π/3)
= -1/2 +(√3/2) i
实部=-1/2
虚部=(√3/2)
幅角=2π/3

化成指数形式,1+√3i=2e^{iπ/3},由于 1-√3i是前者的共轭,故为 2e^{-iπ/3}。从而由 e^{i2π/3}^9=1知,它的十次方就等于它自己,即e^{i2π/3}。这种题一般都是把n次单位根拿出来,求它的 kn+1或2等次方,当然不难。