x/3=y/4=z/6求（xy+yz+xz)/x2+y2+z2=?
问题描述：
x/3=y/4=z/6求（xy+yz+xz)/x2+y2+z2=?
答
设x/3=y/4=z/6=t x=3t,y=4t,z=6t （xy+yz+xz)/x2+y2+z2=(12t+24t+18t)/(9t+16t+36t)=54/61
x/3=y/4=z/6求（xy+yz+xz)/x2+y2+z2=?
设x/3=y/4=z/6=t x=3t,y=4t,z=6t （xy+yz+xz)/x2+y2+z2=(12t+24t+18t)/(9t+16t+36t)=54/61