Question

复数z＝(2-i)(1+i)/i(i为虚数单位)，则｜z|等于

Answer 1

z=(2-i)(1+i)=2-i+2i-i^2=2+i-(-1)=3+i

|z|=根号(3^2+1^2)=根号10

有疑问请追问哈~

Answer 2

z=(2-i)(1+i)/i
=(2+i-i^2)/i
=(3+i)/i
=(3i+i^2)/i^2
=(3i-1)/(-1)
=1-3i
|z|=√[1^2+(-3)^2]
=√10