Question

Find the sum of first 24 terms of an A.P. whose nth term is given by an = 3+2n.​

Answer 1

Step-by-step explanation:

an= 3+2n

Now, put n=1,2,3,...

a1= 3+2(1) = 5

a2= 3+2(2) = 7

a3= 3+2(3) = 9

Thus, the terms of the AP are 5,7,9,.

Here, a = 5 and d = 2

S24= [25+(24 -1)2]

= 12[10+46]

= 12 56

= 672