先化简,在求值(m+n)(m-n)(-m^2-n^2)-(-2m+n)(-2m-n)(4m^2+n^2) 其中m=1,n= -2.
问题描述:
先化简,在求值(m+n)(m-n)(-m^2-n^2)-(-2m+n)(-2m-n)(4m^2+n^2) 其中m=1,n= -2.
答
=(m^2-n^2)(-m^2-n^2)-(4m^2-n^2)(4m^2+n^2)
=-(m^4-n^4)-(16m^4-n^4)
=-(1^4-(-2)^4)-(16*1^4-(-2)^4)
=15