Question

已知x的平方-6x+1=0,求x的平方/x的四次方+x的二次方+1的值

Answer 1

x^2-6x+1=0

x^2+1=6x

同时除以x

x+1/x=6

所以x^2+1/x^2=(x+1/x)^2-2

=6^2-2

=34

x^2/(x^4+x^2+1)

=1/(x^2+1+1/x^2)

=1/(34+1)

=1/35