已知a2-4a+1=0,求3a三次方-11a2+4/(a2+1)
问题描述：
已知a2-4a+1=0,求3a三次方-11a2+4/(a2+1)
答
3a^3-11a2+4/(a2+1)
=3a(4a-1)-11(4a-1)+1/a
=12(4a-1)-3a-44a+11+1/a
=a+1/a-1
=(a^2+1)/a -1
=4a/a-1=3