Differentials

I found a lovely little app called Differentials.  This app shows the steps needed to do take a simple derivative.  As stated, it shows students the basics of differentiating in a step by step manner with arrows and fill in the blanks.  Each step is shown in a concise manner.

 There is a written explanation to accompany each step along with a visual so the student is able to see where each number comes from.  I really like that.  In addition, there are two practice problems and a short multiple choice quiz so students can test their knowledge. 


I love the way the steps are illustrated but I do not like that it only has the one demonstrated example but they can go through the example as many times as they like.  Unfortunately, the practice problems are limited and if you go through the quiz again, the problems are the same.  I would love to see additional practice problems so students can try a variety of problems and get the instant feedback.