设m,n,p是不全相等的任意实数,若x=m^2-np,y=n^2-mp,z=p^2-mn,则x,y,z满足?(大于或小于0)
问题描述:
设m,n,p是不全相等的任意实数,若x=m^2-np,y=n^2-mp,z=p^2-mn,则x,y,z满足?(大于或小于0)
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答
x+y+z=m^2-np+n^2-mp+p^2-mn=1/2(2m^2-2np+2n^2-2mp+2p^2-2mn)=1/2(m^2-2mp+p^2+n^2-2np+p^2+n^2-2mn+m^2)=1/2(m-p)^2+1/2(n-p)^2+1/2(m-n)^2>=0因m,n,p是不全相等的任意实数,则x+y+z>0...