Question

If a is the frist trem, d is the common on different, n is the number of trems the sum to n tems of an AP is ----------​

Answer 1

Answer:

Sn=n/2 (2a+(n-1) d) is the answer.........

Answer 2

Answer:

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

Sn=n/2(a+an)

Step-by-step explanation: