Question

In a geometric progression the third term is 2/9 and the fourth term is 2/27 find (1) the first term and the common ratio (2) the sum of the first 5 term of geometric progression (3) the sum of infinity

Answer 1

I need help

Answer 2

r = (2/27) / (2/9) = 1/3
since ar^2 = 2/9, that means the first term a = 2
S5 = a(1 - r^5)/(1-r)
S∞ = a/(1-r)
So now just plug and chug