Solution - Sum of First n Terms of an AP

Account
Register

Share

Books Shortlist
ConceptSum of First n Terms of an AP

Question

If the sum of the first n terms of an A.P. is 1/2(3n2 +7n), then find its nth term. Hence write its 20th term.

Solution

You need to to view the solution
Is there an error in this question or solution?

Similar questions VIEW ALL

The sum of the first p, q, r terms of an A.P. are a, b, c respectively. Show that \frac { a }{ p } (q – r) + \frac { b }{ q } (r – p) + \frac { c }{ r } (p – q) = 0

view solution

In a school, students thought of planting trees in and around the school to reduce air pollution. It was decided that the number of trees, that each section of each class will plant, will be the same as the class, in which they are studying, e.g., a section of class I will plant 1 tree, a section of class II will plant 2 trees and so on till class XII. There are three sections of each class. How many trees will be planted by the students?

view solution

Find the sum of the odd numbers between 0 and 50.

view solution

Divide 32 into four parts which are in A.P. such that the product of extremes is to the product of means is 7 : 15.

view solution

If Sn denotes the sum of first n terms of an A.P., prove that S30 = 3[S20S10]

view solution

Reference Material

Solution for concept: Sum of First n Terms of an AP. For the course 8th-10th CBSE
S