已知a^2-3a+1=0,
所以a^2+1=3a
a+1/a;
=(a^2+1)/a
=3a/a
=3
(2)a^2+1/a^2
=(a+1/a)^2-2
=9-2
=7
(3)a^2+1/a^2+2a+2/a
=a^2+1/a^2+2(a+1/a)
=7+2*3
=13
已知a^2-3a+1=0,
所以a^2+1=3a
a+1/a;
=(a^2+1)/a
=3a/a
=3
(2)a^2+1/a^2
=(a+1/a)^2-2
=9-2
=7
(3)a^2+1/a^2+2a+2/a
=a^2+1/a^2+2(a+1/a)
=7+2*3
=13