purely imaginary
2011-01-14 3:50 am
let z=m^2-m(1-i)-3(2+i),where m is a real number. If z is purely imaginary, find the value of m.
回答 (2)
2011-01-14 4:03 am
✔ 最佳答案
z=m^2-m(1-i)-3(2+i)=m^2-m+im-6-3i
=(m^2-m-6)+(m-3)i
∵z is purely imaginary,we have
m^2-m-6 = 0
(m-3)(m+2) = 0
∴m = 3 or m= -2
2011-01-14 10:17 pm
m^2 - m(1 - i) - 3(2 + i)
=m^2 - m + mi - 6 - 3i
=(m^2 - m - 6) - (m + 3)i
Since z is purely imaginary, we have m^2 - m - 6 = 0.
So, m = 3 or m = -2
=m^2 - m + mi - 6 - 3i
=(m^2 - m - 6) - (m + 3)i
Since z is purely imaginary, we have m^2 - m - 6 = 0.
So, m = 3 or m = -2
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https://hk.answers.yahoo.com/question/index?qid=20110113000051KK01057