已知z=1−2i,那么1/z=_.
问题描述:
已知z=1−2i,那么
=______. 1 z
答
=1 z
=1 1−2i
=1+2i (1−2i)(1+2i)
=1+2i 5
+1 5
i2 5
故答案为:
+1 5
i.2 5