1. If 1/a-bi = -2+5i, where a and b are real numbers, then b = ?
2. If (k-ki)+(2-i)-3ki is an imaginary number, where k is a real number, then k=?
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complex number
2010-01-09 9:57 pm
回答 (1)
2010-01-09 10:17 pm
✔ 最佳答案
(1) 1/(a - bi) = -2 + 5ia - bi = 1/(-2 + 5i)
= (-2 - 5i)/(4 + 25)
= -2/29 - 5/29 i
b = 5/29
(2) (k - ki) + (2-i) - 3ki
= (k+2) + (-k-1-3k)i is an imaginary number
Hence k + 2 = 0
k = -2
收錄日期: 2021-04-23 23:20:20
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20100109000051KK00700