Question

find the sum to n terms of the A.P whose kth term is 5k+1...thank u

Answer 1

suppose the first term is 'a' & common difference is 'd'.
then
a+(k-1)d=5k+1. ..................(1) eq.
Sum to n terms is this
\[\frac{n}{2}[2a+(n-1)d].\] ................. (2) eq.
I think it should help:D

Answer 2

d=5, a=6

Answer 3

yes we can find a & d by putting k =1 & 2 ..thanks

Answer 4

use the value of a and d by putting it into sum as above

Answer 5

still any doubt.........?