What is the sum of the first 100 numbers of the following sequence- 4,12,36, 108, .........
This question is about geometric sequences. The first step in solving this question is identifying that each term is multiplied by 3 to get to the next term.Therefore since the formula for finding the sum of a certain number of terms is - a(1-rn)/1-r.You would just put the numbers in to the formula. A is the first number so 4, r is the factor by which each term is multiplied by so 3, n is the number of terms which is 100.
If your calculations are correct you should get an answer of 1.03x1048
HG
Related Maths GCSE answers
All answers ▸How do you solve an algebraic equation?
Peter is 180cm tall, correct to 2 significant figures. Alice is 150cm tall, correct to 2 significant figures. What is the upper and lower bound of the difference in their heights?
How do I factorise x^2 - 5x + 6
Complete the square on this equation: 2x^2 + 20x + 15 = 0.