顯然非等差數(shù)列(留存版)
【正文】 ? (n1) = 6n1 Ch24 Example 8. Conjecture a simple formula for an if the first 10 terms of the sequence {an} are 1, 7, 25, 79, 241, 727, 2185, 6559, 19681,59047? Sol： 顯然非等差數(shù)列 後項(xiàng)除以前項(xiàng)的值接近 3 ? 猜測(cè)數(shù)列為 3n ? … 比較： {3n} : 3, 9, 27, 81, 243, 729, 2187,… {an} : 1, 7, 25, 79, 241, 727, 2185,… ? an = 3n 2 , n ? 1 Ch25 ? Summations Here, the variable j is call the index of summation, m is the lower limit, and n is the upper limit.
教學(xué)課件相關(guān)推薦
鄂ICP備17016276號(hào)-1