2015 高考数学第 5 题答案解析

5．设 $a_{1}, a_{2}, \cdots, a_{n} \in \mathbf{R}, n \geq 3$ ．若 $p: a_{1}, a_{2}, \cdots, a_{n}$ 成等比数列；
$q:\left(a_{1}^{2}+a_{2}^{2}+\cdots+a_{n-1}^{2}\right)\left(a_{2}^{2}+a_{3}^{2}+\cdots+a_{n}^{2}\right)=\left(a_{1} a_{2}+a_{2} a_{3}+\cdots+a_{n-1} a_{n}\right)^{2}$ ，则