সমাধান - জ্যামিতিক ধারা

সিরিজের সাধারণ রূপ খুঁজে পেতে, প্রথম পদ: $$a=900$$ এবং সাধারণ অনুপাত: $$r=0.8$$ জ্যামিতিক সিরিজের সূত্রে প্লাগ করুন:

$$a_1=900$$

$$a_2=a_1·r^{n-1}=900\cdot {0.8}^{2-1}=900\cdot {0.8}^1=900\cdot 0.8=720$$

$$a_3=a_1·r^{n-1}=900\cdot {0.8}^{3-1}=900\cdot {0.8}^2=900\cdot 0.6400000000000001=576.0000000000001$$

$$a_4=a_1·r^{n-1}=900\cdot {0.8}^{4-1}=900\cdot {0.8}^3=900\cdot 0.5120000000000001=460.8000000000001$$

$$a_5=a_1·r^{n-1}=900\cdot {0.8}^{5-1}=900\cdot {0.8}^4=900\cdot 0.4096000000000001=368.64000000000004$$

$$a_6=a_1·r^{n-1}=900\cdot {0.8}^{6-1}=900\cdot {0.8}^5=900\cdot 0.3276800000000001=294.9120000000001$$

$$a_7=a_1·r^{n-1}=900\cdot {0.8}^{7-1}=900\cdot {0.8}^6=900\cdot 0.2621440000000001=235.92960000000008$$

$$a_8=a_1·r^{n-1}=900\cdot {0.8}^{8-1}=900\cdot {0.8}^7=900\cdot 0.20971520000000007=188.74368000000007$$

$$a_9=a_1·r^{n-1}=900\cdot {0.8}^{9-1}=900\cdot {0.8}^8=900\cdot 0.1677721600000001=150.9949440000001$$

$$a_{10}=a_1·r^{n-1}=900\cdot {0.8}^{10-1}=900\cdot {0.8}^9=900\cdot 0.13421772800000006=120.79595520000005$$