Posted by **Christopher** on Wednesday, March 11, 2009 at 9:34pm.

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.

## Answer This Question

## Related Questions

- Maths - Eric thinks of 2 sequences.One is geometric and the other arithmetic....
- Sj - Mathematics......Under number patterns-Geometric series If a question goes....
- Precalc - Find the indicated nth term of the geometric sequence. 7th term a5: -2...
- college precalculus I still dont get it - Identify if the given sequence is ...
- precalculus no clue - Identify if the given sequence is arithmetic, geometric, ...
- college precalculus - Identify if the given sequence is arithmetic, geometric, ...
- math Help plz - 1.Given a geometric sequence with a_1=6 and r=2/3, write an ...
- precalculus - Identify if the given sequence is arithmetic, geometric, or ...
- Pre-Cal - 1) Write the first five temrs of the geometric sequence a1 = 2 r=sqrt3...
- Pre-Cal(Please help) - 1) Write the first five temrs of the geometric sequence ...

More Related Questions