(3)已知x/x2＋x＋1＝1/4,x2/x4＋x2＋1的值
问题描述：
(3)已知x/x2＋x＋1＝1/4,x2/x4＋x2＋1的值
答
x/(x²+x+1)=1/(x+1+1/x)=1/4
x+1+1/x=4
x+1/x=3
x²/(x^4+x²+1)
=1/(x²+1/x²+1)
=1/[(x+1/x)²-1]
=1/[3²-1]
=1/8