সমাধান - জ্যামিতিক ধারা

সিরিজের সাধারণ রূপ খুঁজে পেতে, প্রথম পদ: $$a=60$$ এবং সাধারণ অনুপাত: $$r=1.25$$ জ্যামিতিক সিরিজের সূত্রে প্লাগ করুন:

$$a_1=60$$

$$a_2=a_1·r^{n-1}=60\cdot {1.25}^{2-1}=60\cdot {1.25}^1=60\cdot 1.25=75$$

$$a_3=a_1·r^{n-1}=60\cdot {1.25}^{3-1}=60\cdot {1.25}^2=60\cdot 1.5625=93.75$$

$$a_4=a_1·r^{n-1}=60\cdot {1.25}^{4-1}=60\cdot {1.25}^3=60\cdot 1.953125=117.1875$$

$$a_5=a_1·r^{n-1}=60\cdot {1.25}^{5-1}=60\cdot {1.25}^4=60\cdot 2.44140625=146.484375$$

$$a_6=a_1·r^{n-1}=60\cdot {1.25}^{6-1}=60\cdot {1.25}^5=60\cdot 3.0517578125=183.10546875$$

$$a_7=a_1·r^{n-1}=60\cdot {1.25}^{7-1}=60\cdot {1.25}^6=60\cdot 3.814697265625=228.8818359375$$

$$a_8=a_1·r^{n-1}=60\cdot {1.25}^{8-1}=60\cdot {1.25}^7=60\cdot 4.76837158203125=286.102294921875$$

$$a_9=a_1·r^{n-1}=60\cdot {1.25}^{9-1}=60\cdot {1.25}^8=60\cdot 5.9604644775390625=357.62786865234375$$

$$a_{10}=a_1·r^{n-1}=60\cdot {1.25}^{10-1}=60\cdot {1.25}^9=60\cdot 7.450580596923828=447.0348358154297$$