সমাধান - জ্যামিতিক ধারা

সিরিজের সাধারণ রূপ খুঁজে পেতে, প্রথম পদ: $$a=60$$ এবং সাধারণ অনুপাত: $$r=1.8$$ জ্যামিতিক সিরিজের সূত্রে প্লাগ করুন:

$$a_1=60$$

$$a_2=a_1·r^{n-1}=60\cdot {1.8}^{2-1}=60\cdot {1.8}^1=60\cdot 1.8=108$$

$$a_3=a_1·r^{n-1}=60\cdot {1.8}^{3-1}=60\cdot {1.8}^2=60\cdot 3.24=194.4$$

$$a_4=a_1·r^{n-1}=60\cdot {1.8}^{4-1}=60\cdot {1.8}^3=60\cdot 5.832000000000001=349.9200000000001$$

$$a_5=a_1·r^{n-1}=60\cdot {1.8}^{5-1}=60\cdot {1.8}^4=60\cdot 10.4976=629.856$$

$$a_6=a_1·r^{n-1}=60\cdot {1.8}^{6-1}=60\cdot {1.8}^5=60\cdot 18.895680000000002=1133.7408$$

$$a_7=a_1·r^{n-1}=60\cdot {1.8}^{7-1}=60\cdot {1.8}^6=60\cdot 34.012224=2040.7334400000002$$

$$a_8=a_1·r^{n-1}=60\cdot {1.8}^{8-1}=60\cdot {1.8}^7=60\cdot 61.22200320000001=3673.3201920000006$$

$$a_9=a_1·r^{n-1}=60\cdot {1.8}^{9-1}=60\cdot {1.8}^8=60\cdot 110.19960576000003=6611.976345600002$$

$$a_{10}=a_1·r^{n-1}=60\cdot {1.8}^{10-1}=60\cdot {1.8}^9=60\cdot 198.35929036800005=11901.557422080003$$