A spreadsheet is a powerful general purpose software tool, but it works primarily with discrete values, not the more common continuous variables of mathematics, engineering & science

Products do exist which understand continuous variable and the type of work mathematicians, engineers and scientists need to do. For example:

Gnuplot – a plotting and curve fitting tool (Windows version)
Maxima – computer algebra

We start with Gnuplot as a step beyond charts. Lecture slides here.

For more information on Gnuplot: