Prove that a1 ,a2 ,…,an form an AP where an =3+4n Also find the sum of the first 15 terms of AP.
Sir please give me a detailed solution of this question as it is very important for examination
Chapter 9 Question no 12
Here a=7, d=4 and n=15
By usingSn=2n[2a+(n−1)d] we have,