Question

the first and last term of an A.P 12 and 204 respectively if the common difference is 8 find the number of A.P ?

Do this fast 50 pts

Answer 1

Answer:

wait a while sloving this

Answer 2

Answer:

S=2n(a+l) or a+l2S=n          ..(1)

l=a+(n−1)d so that d=n−1l−a         .(2)

Now put for n from (1) in (2),then we get

d = 2S−(l+a)l2−a2