抛物线y=-2x方的焦点坐标是...复数z实部为2 虚部为-1 则5i/z=

问题描述:

抛物线y=-2x方的焦点坐标是...
复数z实部为2 虚部为-1 则5i/z=

F(0,-1/8)
Z=2-i
5i/(2-i)
=5i(2+i)/5
=i(2+i)
=2i-1
=-1+2i