问题
解答题
已知复数z=
|
答案
解法一:将已知复数化为复数三角形式:z=
+1 2
i=cos3 2
+isinπ 3
,ω=π 3
+2 2
i=cos2 2
+isinπ 4 π 4
依题意有zω+zω3
=(cos
+isin7π 12
)+(cos7π 12
+isin13π 12
)13π 12
=(cos
+cos7π 12
)+i(sin13π 12
+sin7π 12
)13π 12
=2cos
(cosπ 4
+isin5π 6
)5π 6
故复数zω+zω3的模为
,辐角主值为2
.5π 6
解法二:zω+zω3
=zω(1+ω2)
=(
+1 2
i)(3 2
+2 2
i)(1+i)2 2
=
(-2
i+3 2
i)1 2
=
(cos2
+isin5π 6
)5π 6