等比数列的性质及应用

• 作 者: 贺长军
• 机 构: 肃南县一中!甘肃 肃南 734400
• 出 处: 甘肃教育
• 发表日期: 2000年Z2期
• 关键词: 实常数 单调递增

性质 1若 {an}为等比数列，公比为 q，则 {}也为等比数列，公比为 .(其中 q是实常数，下同 ) 性质 2若 {an}为等比数列，公比为 q，则 {kan}也为等比数列，公比为 q.(其中 k≠ 0，是实常数 ) 例 1在等比数列 {an}中，已知 a1＋ a2＋ a3＋ a4＋ a5=,，求 a3. 解：设 {an}

Property 1  If {an} is a geometric sequence and the common ratio is q, then {} is also a geometric sequence with a common ratio of . (where q is an actual constant, the same applies hereinafter). Property 2  If {an} is equal The sequence of numbers, the common ratio is q, then {kan} is also the geometric sequence, the common ratio is q. (where k ≠ 0, is an actual constant). Example 1 In the geometric sequence {an}, it is known that a1+a2+a3+a4+ A5=,, find a3. Solution: Set {an}