Question

in AP a=-1 and=1 Sn=0 then find n​

Answer 1

Answer:

Step-by-step explanation:

a= -1  , d = 1    , Sn =0  n =?

Sn = n/2(2a+(n−1)d)

0  = n/2 (2× -1 +(n-1) 1)

0×2 = n ( -2 +(n-1)1)

0 = n (-2n + 2)

0 = -2n² +2n

0 = - 2n (2n -1)

0/-2n = (2n-1)

0 +1 = 2n

1/2 =n

n=1/2