1.(x+ 1/x)^2- 4.5(x+ 1/x)+5=0
2.Show that the equation x^2-3x+3k=k^2 has real roots for any real values of k....
A Math
2007-10-29 2:34 am
回答 (1)
2007-10-29 3:14 am
✔ 最佳答案
1.(x+ 1/x)^2- 4.5(x+ 1/x)+5=0x+ 1/x=2 or x+ 1/x =2.5
x^2-2x+1=0 or x^2-2.5x+1=0
x=1 or x=0.5 or x= 2
2.x^2-3x+3k=k^2
x^2-3x+(3k-k^2)=0
dela=(-3)^2 -4(3k-k^2)
=9+4(k^2-3k)
=9+4[(k-1.5)^2-1.5^2]
=4(k-1.5)^2>0or=0
so
the equation x^2-3x+3k=k^2 has real roots
收錄日期: 2021-04-29 19:41:05
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20071028000051KK03920