Sequences: Sum of an Arithmetic Sequence

To find more learning resources visit https://secondarystem.com/ How to find the sum of an arithmetic sequence or series. We explore the proof of the formula (n/2)*(2a+(n-1)d) and then how to use the formula. I give plenty of worked examples and past paper questions some using just algebra. This is required content for GCSE and iGCSE maths. Explanation of how to find the nth term of an arithmetic sequence: https://youtu.be/tZxHqclUvWQ