posted by Christopher .
I am doing Geometric sequences, but I cannot figure out how to find the Nth term of a geometric sequence.
The problem is A1 = 64, Ak+1 = 1/2Ak
(That is supposed to be A sub one, A sub k + 1, etc.)
The formula for finding the equation is:
An = A1 x R^n-1
The answer is:
An = 128(1/2)^n
I cannot figure out what to do and what happens to the n-1 and how it gets to just n.
Help is greatly appreciated. Thanks.