Question

若x加上x分之一等于3,求x的4次方加上x的平方加上1的和的分之x的2次方?

Answer 1

x+1/x=3

(x+1/x)^2=9

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

x^2+1/x^2=7

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

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

=1/(7+1)

=1/8