Question

X+X分之一等于3,分式X4次方+X平方+1分之X=?

Answer 1

x+1/x=3

两边平方

x^2+2*x*1/x+1/x^2=3^2

x^2+2+1/x^2=9

x^2+1/x^2=7

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

上下除以x^2

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

=1/(7+1)

=1/8