This evaluation type gives detailed positive feedback to help students calculate derivatives of functions. It is only possible to use this evaluation type in positive feedback. Any expression preceded by the differentiation symbol d/dx (or using another variable than x) will be analyzed and appropriate feedback will be given.

The differentiation symbol can be found on the “function” tab of the virtual keyboard.

**Feedback types**

The types of feedback that this evaluation type gives are the following:

Taking a constant or a minus sign outside of the derivative:

Calculating the derivatives of standard functions like the square root, sin, cos, tan, arcsin, arccos, arctan, exp and log:

Use of the sum/difference rule, product/quotient rule and power rule (also for negative exponents and non-square roots)

Use of the chain rule:

This evaluation type has automated feedback, which is shown in the examples above and below.

**Example**

The definition field of this feedback rule should have the variable to which you want to differentiate:

The image below shows an example of how this feedback rule can be used to help the student differentiate a function.

**Test scenarios**

As explained in this article, one should use tex (or asciimathml) in the test cases. In order for your test case to work with the evaluation type fb differentiation, you should use the LaTeX function `\diff{function}{x}`

in your dummy answer. Other functions (like `\frac{\dd function}{\dd x}`

) won’t work.

**More on evaluation types**

An overview of all evaluation types can be found here (for mathematical answers) and here (for text-based answers). More detail on the different fields of a feedback rule can be found here.