解:(m^2+n^2)^2-4m^2*n^2 =m^4+2m^2n^2+n^4-4m^2n^2 =m^4-2m^2n^2+n^4 =(m^2-n^2)^2 =[(m+n)(m-n)]^2 =(m+n)^2(m-n)^2
原式=(m²+n²+2mn)(m²+n²-2mn)=(m+n)²(m-n)²
解:题目是 分解因式 (m^2+n^2)^2-4m^2*n^2