In this tutorial you are shown what an arithmetic progression (A.P.) is and the formulae used to find the nth term and the sum Sn of the first n terms in the sequence with a simple example.

Example in the video

  1. An arithmetic sequence has the terms 5, 9, 13, 17, …
    Find the 21st term and the sum of the first 21 terms, S21.
Arithmetic Progressions - What are they? : ExamSolutions maths revision - youtube Video