Question

The formula for the sum of the first n terms of Ap​

Answer 1

Answer:

Sn = n/2( a + l) if last term is known

Sn = n/2( 2a + (n-1)d) if last term is unknown.

Answer 2

Answer:

You can find sum of n terms by using the following formula:

S = n/2[2a + (n − 1) × d]

hope this helps u..