问题 解答题
计算:
(1)
(1+2i)2+3(1-i)
2+i
;       
(2)
1-
3
i
(
3
+i)
2
答案

(1)

(1+2i)2+3(1-i)
2+i
=
-3+4i+3-3i
2+i
=
i
2+i
=
i(2-i)
(2+i)(2-i)
=
i(2-i)
5
=
1
5
+
2
5
i

(2)

1-
3
i
(
3
+i)
2
=
(
3
+i)(-i)
(
3
+i)
2
=
-i
3
+i
=
-i(
3
-i)
(
3
+i)(
3
-i)
=
(-i)(
3
-i)
4
=-
1
4
-
3
4
i

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