Question

A1 = 2ai = 3ai-1 What is a3, the third term of this geometric series?

Answer 1

Since

`a_i=3a_(i-1)`

then the rate of this geometric series is 3, so we can rewrite the equation in the following form:

`a_{i\text{ }}=3^(i-1)\cdot a_{1\text{ }}=3^(i-1)\cdot2`

Using this expression we calculate the third term of the series,

`a_3=3^(3-1)\cdot2\text{ = 9}\cdot2\text{ =18}`