This is the second video in the series looking at Year 11 Mathematical Methods and Differentiation. Having looked at differentiation from first principles in the first video, we look at the "easier" way to differentiate. This video looks at now only how to differentiate but why we do it. There are lots of practical worked examples which show the ease with which we can differentiate. I also look at how to use the CAS in the best way to differentiate. There is an important discussion about how to find the value of the gradient at a particular point and what this really means. The video is delivered in an easy to understand way.