已知a2-4a+1=0,则a2+1/a2=_.

问题描述:

已知a2-4a+1=0,则a2+

1
a2
=______.

∵a2-4a+1=0,两边都除以a,
则a+

1
a
=4,
∴a2+
1
a2
=(a+
1
a
2-2=42-2=14.