x/（x^2-3x+1）=1/7∴（x²-3x+1)/x=7即x-3+1/x=7x+1/x=10平方得 x²+2+1/x²=100x²+1/x²=98（x^4+x^2+1）/x²=x²+1+1/x²=98+1=99∴x^2/（x^4+x^2+1）=1/99