09
January 已知m+1/m=√5，求m-1/m的值
已知m+1/m=√5，求m-1/m的值
已知m+1/m=√5
(m+1/m)^2=5,m^2+(1/m)^2=3,m^2+(1/m)^2-2=3-2
(m-1/m)^2=1,m-1/m=+1,-1
最佳答案 - 由投票者2008-09-13 16:22:03选出
已知m+1/m=√5，求m-1/m的值
解：将m+1/m=√5的两边平方得：
m +1/m =3
故（m-1/m) =m -2+1/m =3-2=1
∴m-1/m=±1.
3-√5/2
1-√5/2
1-4(2±√2)
#If you have any other info about this subject , Please add it free.# |
Posted by WKTD under gznq.com | Comment now » |
