先化简,再求值（过程）[(m-n/m^2-2mn+n^2)-(mn+n^2/m^2-n^2)]*(mn/n-1),其中m

[(m-n/m^2-2mn+n^2)-(mn+n^2/m^2-n^2)]*(mn/n-1)
={[m-n/(m-n)^2)]-[n(m+n)/(m+n)(m-n)]*(mn/n-1)
=[1/(m-n)- n/(m-n)] * mn/(n-1)
=(1-n)/(m-n) * mn/(n-1)
= -(mn)/(m-n)
因为mn =(-√3-2)(-√3+2) = -1
m-n = (-√3-2)-(-√3+2) = -4
所以原式 = -(mn)/(m-n) = -（-1）/ -4 = -1/4

原式=[m-n/(m-n)^2-n(m+n)/(m+n)(m-n)]*mn/n-1
=(1/m-n-n/m-n)*mn/n-1
=1-n/m-n*mn/n-1
=mn/n-m
代入m.n值最后计算得-1/4