Question

in an ap t1=22,tn= -11,sn= 66, find n

Answer 1

this is ur required solution

Answer 2

Answer:

n=12

Step-by-step explanation:

a+(n-1)d=an

22+(n-1)d=-11

(n-1)d=-33

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

66=n/2(2(22)+(n-1)d)

66×2=n(44-33)

132=n(11)

n=132/11

n=11