作业帮若x^2-5x-1=0,则x^2−1/x^2=________．
来源：学生作业帮助网 编辑：作业帮 时间：2024/12/01 10:09:29
x){ѽ"H״B@iL OMP ȶ{lIӠ_`gC Og/xcBXYgÓK|
[SP6 #sF m]bg v>ndlP`5:L6BuY$ف| 4v)
若x^2-5x-1=0,则x^2−1/x^2=________．
若x^2-5x-1=0,则x^2−1/x^2=________．
若x^2-5x-1=0,则x^2−1/x^2=________．
因为x^2-5x-1=0
所以x-1/x=5
x^2+1/x^2=27
(x+1/x)^2=29
x+1/x=正负根号28
所以x^2-1/x^2=(x+1/x)(x-1/x)=正负5倍根号29