已知m/n=5/3,求分式m/(m+n)+m/(m-n)-n^2/(m^2-n^2)的值
问题描述：
已知m/n=5/3,求分式m/(m+n)+m/(m-n)-n^2/(m^2-n^2)的值
答
m/(m+n)+m/(m-n)-n^2/(m^2-n^2)=m(m-n)/(m+n)(m-n)+m(m+n)/(m-n)(m+n)-n^2/(m^2-n^2)=（m(m-n)+m(m+n)）/(m^2-n^2)-n^2/(m^2-n^2)=（2m^2)）/(m^2-n^2)-n^2/(m^2-n^2)=(2m^2-n^2)/(m^2-n^2)m/n=5/3m=5n/3带入=(2（5n...