Let S_n be the sum of the first n terms of an AP. If S_ 2n =3n+14n^2, then what is the common difference?

NDA 2019 Mathematics question

Let be the sum of the first n terms of an AP. If , then what is the common difference?

Answer: (C)

Put : . For an AP, $ =

Create a free account to read the complete working, and practise questions like this in a timed test.

Question ID VK-029084