已知:n分之m=3分之5,求(m+n分之m) + (m-n分之m) - (m方-n方,分之n方)
问题描述：
已知:n分之m=3分之5,求(m+n分之m) + (m-n分之m) - (m方-n方,分之n方)
答
n分之m=3分之5m/n=5/3m/(m+n)+m/(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)=[2m^2/n^2-1]/[m^2/n^2-1]=[2*(5/3)^2-1]/[(5/3)^2-1]=(50/9-1)/...