Question

已知x+1/x=3,求x^2/(x^4+x^2+1)的值.重点在最后一步,怎么变化的,我不理解,求说明!

Answer 1

x²/(x^4+x²+1)=1/(x²+1/x²+1)

x+1/x=3

x²+1/x²+2=9

x²+1/x²=7

所以x²/(x^4+x²+1)=1/(x²+1/x²+1)=1/（7+1）=1/8