解答 - 几何数列

要找到系列的通用形式，将第一项：$$a=276$$ 和公比：$$r=1.3478260869565217$$ 插入几何级数的公式：

$$a_1=276$$

$$a_2=a_1·r^{n-1}=276\cdot {1.3478260869565217}^{2-1}=276\cdot {1.3478260869565217}^1=276\cdot 1.3478260869565217=372$$

$$a_3=a_1·r^{n-1}=276\cdot {1.3478260869565217}^{3-1}=276\cdot {1.3478260869565217}^2=276\cdot 1.8166351606805293=501.3913043478261$$

$$a_4=a_1·r^{n-1}=276\cdot {1.3478260869565217}^{4-1}=276\cdot {1.3478260869565217}^3=276\cdot 2.44850826004767=675.7882797731569$$

$$a_5=a_1·r^{n-1}=276\cdot {1.3478260869565217}^{5-1}=276\cdot {1.3478260869565217}^4=276\cdot 3.3001633070207723=910.8450727377332$$

$$a_6=a_1·r^{n-1}=276\cdot {1.3478260869565217}^{6-1}=276\cdot {1.3478260869565217}^5=276\cdot 4.448046196419302=1227.6607502117274$$

$$a_7=a_1·r^{n-1}=276\cdot {1.3478260869565217}^{7-1}=276\cdot {1.3478260869565217}^6=276\cdot 5.995192699521668=1654.6731850679803$$

$$a_8=a_1·r^{n-1}=276\cdot {1.3478260869565217}^{8-1}=276\cdot {1.3478260869565217}^7=276\cdot 8.080477116746595=2230.2116842220603$$

$$a_9=a_1·r^{n-1}=276\cdot {1.3478260869565217}^{9-1}=276\cdot {1.3478260869565217}^8=276\cdot 10.891077853006282=3005.9374874297337$$

$$a_{10}=a_1·r^{n-1}=276\cdot {1.3478260869565217}^{10-1}=276\cdot {1.3478260869565217}^9=276\cdot 14.679278845356292=4051.4809613183365$$