What are the formulaes for:
Arithmatic progression, if i know how many numbers there are, their sum, and their product?
and
Geometric progression, if i know the second term and the sum to infinity?
First of all I think we need to know the first term and common difference." Arithmatic progression, if i know how many numbers there are, their sum?":
With that we could tell you the formula, but I think its better you consult your text book. Text books generally have a flow that makes it easy to understand, remember and apply.
I am sorry, this could be hard. I have no idea of this."and their product?"
I think its better if you post a problem that demands the use of these formulae. Can you post one?
Afterthought: I think you have a problem at hand and thus you want to know the formulae. So could you post those exactly as in the question?"and Geometric progression, if i know the second term and the sum to infinity?"