Symbolic Math Toolbox™ uses the MuPAD® language as part of its underlying computational engine. The language has an extensive set of functions that are optimized for creating and operating on symbolic math expressions.
Prior to the R2016a release of MATLAB® (March 2016), the MuPAD Notebook was the primary interface for performing and documenting symbolic math calculations. Starting in R2016a, the recommended approach is to use the MATLAB Live Editor.
The MATLAB Live Editor is an interactive way to create, edit, and run MATLAB code. In a single environment your symbolic math computations are displayed in mathematical typeset, along with formatted text, equations, images, and hyperlinks. You can share live scripts with others to accelerate exploratory analysis, create interactive narratives, and teach with interactive documents.
Alternatively you can continue to use the MuPAD language directly in the MuPAD Notebook. You can launch the MuPAD Notebook using the MATLAB function
mupad or by clicking the Apps tab in the MATLAB Toolstrip.