Autograph is a fantastic tool for demonstrating the gradient function.
You can easily create a function and attach a point with a tangent to the function, and then move this point to show the gradient at a point.
Alternatively you can use the slow plot feature and the gradient function tool (in Advanced mode) to dynamically create the gradient function. This handily pauses on the key points (stationary and inflection points).
Whenever I teach differentiation I find that students are able to do the process fairly easily, but understanding that differentiation tells us the gradient function and what this actually means is something that students can find difficult to grasp. Here are a few interactive ideas for developing this sense, making use of Geogebra, Desmos and Autograph.
Autograph Tangents and Slow Plot
I usually get the students to draw what they think the derivative (gradient) function will look like, and then use the slow plot to reveal if they are correct. It is great to use lots of weird and wonderful functions here too!
I am a maths teacher looking to share good ideas for use in the classroom, with a current interest in integrating educational research into my practice.