Question

In a G.P the second and fourth term are 0.04 and 1 respectively find the (1) common ratio (2) first term(simple formula; s s2)

Answer 1

r^2 = 1/.04 = 25
r = ±5
a = .04/r = ±0.008

Answer 2

T2=0•04, T4=1, r=?, a=?
ar^3 =1
ar^1 0•04
√r^2 =√25
r=5
To find a,put r=2 into equ (I)
ar^3 =1
a(5)^3=1
125a=1
125 125
a=0•008