※ 引述《CBH (吸逼A去)》之銘言：
: http://imgur.com/7smsPPE
: 抱歉圖檔解析度不高
: 第一題可能不清楚
: 題目是滿足An+1 = 2An + 5‧3^n 求一般項 An = ?
A_n = p 2^n + q 3^n
=> q 3 * 3^n = 2 q 3^n + 5 * 3^n
=> 3q = 2q + 5
=> q = 5
A_1 = 5
= 2p + 15
=> p = -5
=> A_n = -5 * 2^n + 5 * 3^n
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