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已知m/n=5/3,求分式m/(m+n)+m/(m-n)-n^2/(m^2-n^2)的值

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已知m/n=5/3,求分式m/(m+n)+m/(m-n)-n^2/(m^2-n^2)的值
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=5/3
m=5n/3带入
=(2(5n/3)^2-n^2)/((5n/3)^2-n^2)
=(2(5n/3)^2-n^2)/((5n/3)^2-n^2)
=(41n^2/9)/(16N^2/9)
=41/16