Question

已知x+1/x=3,求x的平方/3x的四次方+x的二次方+3的值

Answer 1

x+1/x=3 两边平方得到x^2+1/x^2=7 所以x^2/(3x^4+x^2+3) =1/[3(x^2+1/x^2)+1] =1/22