সমাধান - জ্যামিতিক ধারা

সিরিজের সাধারণ রূপ খুঁজে পেতে, প্রথম পদ: $$a=140$$ এবং সাধারণ অনুপাত: $$r=1.4$$ জ্যামিতিক সিরিজের সূত্রে প্লাগ করুন:

$$a_1=140$$

$$a_2=a_1·r^{n-1}=140\cdot {1.4}^{2-1}=140\cdot {1.4}^1=140\cdot 1.4=196$$

$$a_3=a_1·r^{n-1}=140\cdot {1.4}^{3-1}=140\cdot {1.4}^2=140\cdot 1.9599999999999997=274.4$$

$$a_4=a_1·r^{n-1}=140\cdot {1.4}^{4-1}=140\cdot {1.4}^3=140\cdot 2.7439999999999993=384.1599999999999$$

$$a_5=a_1·r^{n-1}=140\cdot {1.4}^{5-1}=140\cdot {1.4}^4=140\cdot 3.8415999999999992=537.8239999999998$$

$$a_6=a_1·r^{n-1}=140\cdot {1.4}^{6-1}=140\cdot {1.4}^5=140\cdot 5.378239999999998=752.9535999999997$$

$$a_7=a_1·r^{n-1}=140\cdot {1.4}^{7-1}=140\cdot {1.4}^6=140\cdot 7.529535999999998=1054.1350399999997$$

$$a_8=a_1·r^{n-1}=140\cdot {1.4}^{8-1}=140\cdot {1.4}^7=140\cdot 10.541350399999995=1475.7890559999994$$

$$a_9=a_1·r^{n-1}=140\cdot {1.4}^{9-1}=140\cdot {1.4}^8=140\cdot 14.757890559999993=2066.104678399999$$

$$a_{10}=a_1·r^{n-1}=140\cdot {1.4}^{10-1}=140\cdot {1.4}^9=140\cdot 20.66104678399999=2892.5465497599985$$