Introduction to Sequences

Geometric Sequence = A sequence of numbers that you multiply by a number to get the next term.

e.g    if you have the sequence    5,10,20,40,80     

call the sequence 'a'

a1 = 5

a2 = 10 a2 = a1 x 2

a3 = 20 a3 = a2 x 2

a4 = 40 a4 = a3 x 2

a5 = 80 a5 = a4 x 2

if the sequence continued, we would get a100 = a99 x 2

in general, we would have ak+1 = ak x 2

this is called an iterative or inductive formula.

Arithmetic Sequence…