已知a,x,b,与b,y,c成等差数列,而a,b,c,成等比,xy≠0,则a/x+b/y的值为多少

问题描述:

已知a,x,b,与b,y,c成等差数列,而a,b,c,成等比,xy≠0,则a/x+b/y的值为多少

由题得:a=ax=a+qb=a+2qy=a+2q+pc=a+2q+2p又因为c/b=b/a所以(a+2q+2p)/(a+2q)=(a+2q)/a解得a=2q^2/(p-q)所以x=(pq+q^2)/(p-q)b=2pq/(p-q)y=(pq+p^2)/(p-q)所以a/x+b/y=2q/(...