 Hi and welcome to the session. Let's work out the following question. The question says if the nth term of an AP is 2n plus 1, find the sum of first n terms of the AP. Let us start with a solution to this question. We have nth term that is an is equal to 2n plus 1 that is given to us in the question. Therefore, a1 will be equal to 2 into 1 plus 1 that is equal to 3. a2 will be equal to 2 into 2 plus 1 that is equal to 5. a3 will be equal to 2 into 3 plus 1 that is 7. Therefore, the common difference that is small d is equal to a2 minus a1 that is equal to 5 minus 3 and that is equal to 2. Therefore, sum of first n n terms is Sn that is equal to n by 2 into a plus n minus 1 into d that is equal to n by 2 into 3 plus n minus 1 into 2 that is equal to n by 2 into 3 plus 2n minus 2 and that is equal to n by 2 into 1 plus 2n. So, our answer to this question is that Sn is equal to n by 2 into 1 plus 2n. So, I hope that you understood the solution and enjoyed the session. Have a good day.