Question

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)

Answer 1

(m+n分之m) + (m-n分之m) - (m方-n方,分之n方)

=m(m-n)/(m^2-n^2)+m(m+n)/(m^2-n^2)-n^2/(m^2-n^2)

=(m^2-mn+m^2+mn-n^2)/(m^2-n^2)

=(2m^2-n^2)/(m^2-n^2)

=[2(m/n)^2-1]/[(m/n)^2-1]

=(50/9-1)/(25/9-1)

=(41/90/(16/9)=41/16.