已知x/(x^2+1)=1/3,求(x^2)/(x^4+1)的值
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已知x/(x^2+1)=1/3,求(x^2)/(x^4+1)的值
已知x/(x^2+1)=1/3,求(x^2)/(x^4+1)的值
已知x/(x^2+1)=1/3,求(x^2)/(x^4+1)的值
由题意知 (x^2+1) /x =3
(x^4+1) /x^2=[(x^2+1)^2-2x^2 ] /x^2=9-2=7
所求式为 1/7
x=0不为x/(x^2+1)=1/3
1/[(1/x)+x]=1/3
(1/x)+x=3
(1/x)^2+x^2=[(1/x)+x]^2-2
(x^2)/(x^4+1)
=1/[(x^2)+(1/x^2)]