(a+bi)(c+di)∈R ＜＝＝＞__________ 怎么解,

题目

(a+bi)(c+di)∈R ＜＝＝＞__________ 怎么解,

答案

(a+bi)(c+di)=ac-bd+(ad+bc)i)∈R
所以ad+bc=0
(a+bi)(c+di)∈R ＜＝＝＞ad+bc=0