3+4.5+6.75 is a GP find an expression for Tn and hence evaluate T6 to 3sf
Don't know it
Terms are:
3 , 4.5 , 6.75...
4.5 / 3 = 1.5
6.75 / 4.5 = 1.5
This is GP with first term t = 1 and common ratio r = 1.5
The n-th term of GP:
tn = t ∙ r ⁿ ⁻ ¹
t6 = t ∙ r ⁶ ⁻ ¹ = t ∙ r ⁵ = 3 ∙ 1.5 ⁵ = 3 ∙ 7.59375 = 22.78125