m2次-n2次的因式分解?

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

because
(m+n)(m-n)
=m*m-mn+mn-n*n

-mn+mn=0

so
(m+n)(m-n)
=m*m-n*n
=m^2-n^2

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

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

2007-08-17 11:35:27 補充：
覆數(m n)(m - n)= m^2 mn - mn - n^2= m^2 - n^2