已知a2-4a+1=0,则a2+1/a2=_.
问题描述:
已知a2-4a+1=0,则a2+
=______. 1 a2
答
∵a2-4a+1=0,两边都除以a,
则a+
=4,1 a
∴a2+
=(a+1 a2
)2-2=42-2=14.1 a