若ax=by=cz,求证:a3x2+b3y2+c3z2=(a+b+c)3(x+y+z)2
发布网友
发布时间:2024-10-04 10:43
我来回答
共1个回答
热心网友
时间:2024-10-05 13:57
设ax=by=cz=t,则a=xt,y=bt,z=ct,
a3x2+b3y2+c3z2=x3t3x2+y3t3y2+z3t3z2=xt3+yt3+zt3=t3(x+y+z),
(a+b+c)3(x+y+z)2=(xt+yt+zt)3(x+y+z)2=t3(x+y+z)3(x+y+z)2=t3(x+y+z).
所以a3x2+b3y2+c3z2=(a+b+c)3(x+y+z)2.