Partial derivatives, gradient and tangential plane are central subjects in multidimensional analysis (not only) in engineering maths. This collection of applets will support the visulization of these different aspects. STACK problems will be published as during 2025.
The ideas where shown in the talk of Meike Akveld and Wigand Rathmann at the International Meeting of the STACK Community 2025 in Durham (Program, Tuesday)
Here more examples demonstrating derivatives will be found here.