সমাধান - জ্যামিতিক ধারা

সিরিজের সাধারণ রূপ খুঁজে পেতে, প্রথম পদ: $$a=60$$ এবং সাধারণ অনুপাত: $$r=0.8$$ জ্যামিতিক সিরিজের সূত্রে প্লাগ করুন:

$$a_1=60$$

$$a_2=a_1·r^{n-1}=60\cdot {0.8}^{2-1}=60\cdot {0.8}^1=60\cdot 0.8=48$$

$$a_3=a_1·r^{n-1}=60\cdot {0.8}^{3-1}=60\cdot {0.8}^2=60\cdot 0.6400000000000001=38.400000000000006$$

$$a_4=a_1·r^{n-1}=60\cdot {0.8}^{4-1}=60\cdot {0.8}^3=60\cdot 0.5120000000000001=30.720000000000006$$

$$a_5=a_1·r^{n-1}=60\cdot {0.8}^{5-1}=60\cdot {0.8}^4=60\cdot 0.4096000000000001=24.576000000000004$$

$$a_6=a_1·r^{n-1}=60\cdot {0.8}^{6-1}=60\cdot {0.8}^5=60\cdot 0.3276800000000001=19.660800000000005$$

$$a_7=a_1·r^{n-1}=60\cdot {0.8}^{7-1}=60\cdot {0.8}^6=60\cdot 0.2621440000000001=15.728640000000006$$

$$a_8=a_1·r^{n-1}=60\cdot {0.8}^{8-1}=60\cdot {0.8}^7=60\cdot 0.20971520000000007=12.582912000000004$$

$$a_9=a_1·r^{n-1}=60\cdot {0.8}^{9-1}=60\cdot {0.8}^8=60\cdot 0.1677721600000001=10.066329600000005$$

$$a_{10}=a_1·r^{n-1}=60\cdot {0.8}^{10-1}=60\cdot {0.8}^9=60\cdot 0.13421772800000006=8.053063680000005$$