解:
a²-3a+1=0
a²+1=3a
(a²+1)×1/a=3a×1/a
a²×1/a+1×1/a=3
a+(1/a)=3
[a+1(/a)]²=3²
a²+2×a×1/a+(1/a²)=9
a²+2+(1/a²)=9
a²+(1/a²)=9-2=7
(a^4+1)/a²=a^4/a²+1/a²
=a²+(1/a²)
=7
a²/(a^4+1)=1/7
解:∵a^2-3a+1=0
∴a^2+1=3a 两边同除以a 即 a+1/a=3
(a+1/a)^2=9 解得a^2+1/a^2=7
又∵a^2/(a^4+1)=1/(a^2+1/a^2)=1/7