(Q6).For each geometric progression find the common ratio ‘r’, and then find a
n
.
(iii) -1, -3, -9, -27, ……
Given G.P. = -1, -3, -9, -27, ……
a = -
, r =
a
2
a
1
=
-
-
=
a
n
= a.r
n-1
= (-
) ×
n-1
∴ r =
; a
n
= (-
) ×
n-1
Clear