Posted by **Anonymous** on Thursday, April 17, 2008 at 2:32pm.

1) If the sum of the first n terms of a series is Sn where Sn=2nē-n,

(a)prove that the series is an AP, stating the first term and the common difference;

(b)find the sum of the terms from the 3rd to the 12th inclusive

2) In an AP the 6th term is half the 4th term and the 3rd term is 15.

(a)Find the first term and the common difference;

(b)How many terms are needed to give a sum that is less than 65?

Please help

## Answer This Question

## Related Questions

- math - 1) If the sum of the first n terms of a series is Sn where Sn=2nē-n, (a)...
- Math(arithmetic & Geometric Series) - 1)The sum of 6 terms of an arithmetic ...
- Math - the sum of the first n terms of an arithmetic series is -51. the series ...
- math studies - An arithmetic series has a first term of -4 and a common ...
- math - The sum of the first 20 terms of an arithmetic series is identical to the...
- arithmetic - 1. The first and last term of an A.P are, a and l respectively, ...
- arithmetic - 1. The first and last term of an A.P are, a and l respectively, ...
- math - the "k"th term of a series, Sk=a 1-r^k/1-r, is the sum of the first "k" ...
- math help!! - the first term in a geometric series is 4 and the sum of the first...
- Math. - The first term of a geometric series is 4 and the sum of the first three...

More Related Questions