Question

. Find the sum of first 15th term of an AP of which an= 3+4n​

Answer 1

Answer:

?????!??????!????????

Answer 2

Answer:

Step-by-step explanation:

The nth term of the AP =an=3+4n

So first term a=3+4×1=7

Common difference d=4

So sum of first 15 terms=15/2{2a+14d}

=(15/2)(2×7+14×4)

= (15/2)(14+56)

=(15/2)(70)=15×35=525

So sum of the first 15 terms of the AP is 525.

Hope you got it