সমাধান - জ্যামিতিক ধারা

সিরিজের সাধারণ রূপ খুঁজে পেতে, প্রথম পদ: $$a=60$$ এবং সাধারণ অনুপাত: $$r=1.2$$ জ্যামিতিক সিরিজের সূত্রে প্লাগ করুন:

$$a_1=60$$

$$a_2=a_1·r^{n-1}=60\cdot {1.2}^{2-1}=60\cdot {1.2}^1=60\cdot 1.2=72$$

$$a_3=a_1·r^{n-1}=60\cdot {1.2}^{3-1}=60\cdot {1.2}^2=60\cdot 1.44=86.39999999999999$$

$$a_4=a_1·r^{n-1}=60\cdot {1.2}^{4-1}=60\cdot {1.2}^3=60\cdot 1.7279999999999998=103.67999999999998$$

$$a_5=a_1·r^{n-1}=60\cdot {1.2}^{5-1}=60\cdot {1.2}^4=60\cdot 2.0736=124.416$$

$$a_6=a_1·r^{n-1}=60\cdot {1.2}^{6-1}=60\cdot {1.2}^5=60\cdot 2.4883199999999994=149.29919999999996$$

$$a_7=a_1·r^{n-1}=60\cdot {1.2}^{7-1}=60\cdot {1.2}^6=60\cdot 2.9859839999999993=179.15903999999995$$

$$a_8=a_1·r^{n-1}=60\cdot {1.2}^{8-1}=60\cdot {1.2}^7=60\cdot 3.583180799999999=214.99084799999994$$

$$a_9=a_1·r^{n-1}=60\cdot {1.2}^{9-1}=60\cdot {1.2}^8=60\cdot 4.2998169599999985=257.9890175999999$$

$$a_{10}=a_1·r^{n-1}=60\cdot {1.2}^{10-1}=60\cdot {1.2}^9=60\cdot 5.1597803519999985=309.5868211199999$$