Question

若三分之x=二分之y=四分之z，求x的二次方+y的二次方+z的二次方分之xy+yz+xz的值

Answer 1

设 x/3=y/2=z/4=k
x=3k,y=2k,z=4k
(xy+yz+xz)/(x^2+y^2+z^2)
=(6+8+12)/(9+4+16)
=26/29

Answer 2

设 x/3=y/2=z/4=k
则 x=3k,y=2k,z=4k
(xy+yz+xz)/(x^2+y^2+z^2)
=(6+8+12)k^2/(9+4+16)k^2
=26/29