সমাধান - জ্যামিতিক ধারা

সিরিজের সাধারণ রূপ খুঁজে পেতে, প্রথম পদ: $$a=65$$ এবং সাধারণ অনুপাত: $$r=1.4$$ জ্যামিতিক সিরিজের সূত্রে প্লাগ করুন:

$$a_1=65$$

$$a_2=a_1·r^{n-1}=65\cdot {1.4}^{2-1}=65\cdot {1.4}^1=65\cdot 1.4=91$$

$$a_3=a_1·r^{n-1}=65\cdot {1.4}^{3-1}=65\cdot {1.4}^2=65\cdot 1.9599999999999997=127.39999999999998$$

$$a_4=a_1·r^{n-1}=65\cdot {1.4}^{4-1}=65\cdot {1.4}^3=65\cdot 2.7439999999999993=178.35999999999996$$

$$a_5=a_1·r^{n-1}=65\cdot {1.4}^{5-1}=65\cdot {1.4}^4=65\cdot 3.8415999999999992=249.70399999999995$$

$$a_6=a_1·r^{n-1}=65\cdot {1.4}^{6-1}=65\cdot {1.4}^5=65\cdot 5.378239999999998=349.5855999999999$$

$$a_7=a_1·r^{n-1}=65\cdot {1.4}^{7-1}=65\cdot {1.4}^6=65\cdot 7.529535999999998=489.41983999999985$$

$$a_8=a_1·r^{n-1}=65\cdot {1.4}^{8-1}=65\cdot {1.4}^7=65\cdot 10.541350399999995=685.1877759999996$$

$$a_9=a_1·r^{n-1}=65\cdot {1.4}^{9-1}=65\cdot {1.4}^8=65\cdot 14.757890559999993=959.2628863999995$$

$$a_{10}=a_1·r^{n-1}=65\cdot {1.4}^{10-1}=65\cdot {1.4}^9=65\cdot 20.66104678399999=1342.9680409599994$$