1. The problem statement, all variables and given/known data Hi there, question asks "What is the difference between the sum to ten terms and the sum to infinity. a = sqroot 2 r = sqroot 2/2 The sum to ten terms, I worked out as 31 + 31 sqroot 2 The sum to infinity, I worked out as 2 sqroot 2 + 2 2. Relevant equations Is there one equation to cover this type of problem or do I need to subtract one equation from the other to get one equation and hence one answer? 3. The attempt at a solution Totally confused?