Question

in an arithmetic progression, if tn = 2n -1, then what is Sn ?

Answer 1

T1=2-1=1=a
T2=4-1=3
D=3-1=2
Now, sn =n/2(2(1)+(n-1) (2))
=n(1+n-1)
=n2
I hope its helpful to you......