This video introduces the concept of radius of convergence, and takes you through the step-by-step process using the Ratio Test that you'll use for these problems. If you don't remember the ratio test, review this chapter.
Interval of Convergence
Extending on the previous video, these interval of convergence problems start the same way as radius of convergence problems, except that you then must test the endpoints to see if they result in a convergent series.
If you do not have an account, you should get one, because it is awesome! You can save a playlist for each test or each chapter, and save your "greatest hits" into a "watch right before the final" list (not that we recommend cramming, but when in Rome...)