Question

The sum of first 24 terms of the list of number whose and its term is given by an=3+2n

Answer 1

Step-by-step explanation:

an = 3 + 2n a1 = 3 + 2 = 5 a2 = 3 + 2 x 2 = 7 a3 = 3 + 2 x 3 = 9 List of numbers becomes 5, 7, 9. 11, … Here,7 – 5 = 9 – 7 = 11 – 9 = 2 and soon. So, it forms an A.P. with common difference d = 2. To find S24, we have n = 24, a = 5, d = 2. S24 = (24/2) [2 x 5 + (24 – 1) x 2] = 12 [10 + 46] = 672 So, sum of first 24 terms of the list of numbers is 672.