首页 > 留学知识库

问题: 复数求值问题

z=-2/(1+根号3i) 求1+z+z^+....+z^2008 谢谢

解答:

上面回答错了。
z=-2/(1+i√3i)=(-1+i√3)/2
z^2=(1-i2√3-3)/4=(-1-i√3)/2
z^3=z*z^2=(1+3)/4=1
z^4=z*z^3=z, z^5=z^2, z^6=1
又1+z+z^2=0,所以
1+z+z^2+…+z^2008=(1+z+z^2)+(z^3+z^4+z^5)+…+(z^2004+z^2005+z^2006)+z^2007+z^2008
=(1+z+z^2)+(1+z+z^2)+…+(1+z+z^2)+z^2007+z^2008
=z^2007+z^2008=1+z=1+(-1+i√3)/2=(1+i√3)/2