Show that each one of the following progressions is a G.P. Also, find the common ratio in each case :

i. 4, -2, 1, ,….


ii.


iii.


iv.

(i) Let a = 4, b = -2, c = 1.


In GP, b2=ac


(-2)2 = 4.1


4 = 4


Common ratio = r


(ii) Let , b = -6, c = -54.


In GP, b2=ac



36 = 36


Common ratio = r


(iii) Let a = a,


In GP, b2=ac




Common ratio


(iv) Let


In GP, b2=ac




Common ratio


1