Question

In an AP first term a and last term an then write the sum of first n terms of an AP

Answer 1

Sn=
$\frac{n}{2} (a + an)$

Answer 2

Answer:

Sn = n/2(2a + (n - 1)d)

• Sn = Sum of n terms

• a = first term

• d = common difference

• an = last term [ Given in question ]

Sn = n/2(a + an)