m^2+k^2/m^2=n^2+k^2/n^2通分：(m^4+k^2)/m^2=(n^4+k^2)/n^2交叉相乘：m^4*n^2+k^2*n^2=m^2*n^4+m^2*k^2移向：m^4*n^2-m^2*n^4=m^2*k^2-k^2*n^2提取公因式：m^2*n^2*(m^2-n^2)=k^2*(m^2-n^2)化简：m^2*n^2=k^2...