Question

Write explicit formula in geometric sequence -2, 8, -32, 128

Answer 1

So first thing we need, is the formula for a geometric sequence...

\[\large a_n = a_1 \times r^{n - 1}\]

where 'n' is the term we are working with and 'r' is the common ratio *and a1 is the frst term

So we need to solve for 'r' ...what is the common ratio here? how do we get to the next number over and over again?