You are told that and .
By definition and
Next work out and and in terms of and and the solve the simultaneous equations
Edit: Sum of an arithmetic sequence is
The ratio of the 5th term to the 12th term of a sequence in an arithmetic progression is 6/13. If each of this sequence is positive, and the product of the 1rst term and the 3rd term is 32, find the sum of the first 100 terms of this sequence.
Hope someone can help, I'm studying for my math final. Which formula should I use?