若m,n互為相反數,則1/2m^2+mn+1/2n^2的值是______

若m,n互為相反數,則1/2m^2+mn+1/2n^2的值是______

1/2m^2+mn+1/2n^2
=1/2(m^2+2mn+n^2)
=1/2(m+n)²;
因為m、n互為相反數,所以m+n=0
所以=1/2(m+n)²;
=0
若m,n互為相反數,則1/2m^2+mn+1/2n^2的值是__0____