2000年高考数学卷(理科)第20题第1小题:已知数列{Cn},其中Cn=2n+3n,且数列{Cn+1-pCn}为等比数列,求常数p.此题的背景来源于这样一个简单的事实:对于数列{an},若{an+1-pan}是以q为公比的等比数列(p≠0,q≠0),且a2-pa1≠0,则{an+1-qan}是以p为公比的等比数列.证明　∵　{an+1-pan In the 2000 college entrance examination mathematics volume (science) 20th problem 1th problem: Known sequence {Cn}, where Cn=2n+3n, and the sequence {Cn+1-pCn} is an array of equal numbers, find the constant p. The background is derived from the simple fact that for the series {an}, if {an+1-pan} is a series of equal proportions of q (p≠0, q≠0), and a2-pa1≠0 , then {an+1-qan} is the geometric progression with p as a ratio. Prove that {an+1-pan