What's the difference between Gnuplot, MuPAD, and my calculator?
Gnuplot is a general purpose graphing and plotting application. Like a graphical scientific calculator, it plots equations. Like others, it can also solve for single or multiple variables, can do numerical integration and find the values of derivatives. Unlike most calculators, it can plot 3D equations, use data files, output to numerous devices, etc.. In other words, it's a lot more flexible than your TI85.
MuPAD is a symbolic mathematics package. It does not (necessarily) rely on numerical methods to solve integrals or other equations. For example, whereas a calculator may give you the (x,y) coordinates as an "answer" to a derivative, MuPAD can give the equation of the derivative.
R is the powerful statistics package modeled after S.
Why should you use one of these packages instead of your calculator? Well, that's what the entire math section is for! It's still very much beta, but the next section (complete except for pretty graphics) will try to answer this question. I'm finishing off the gnuplot/limits portion now, and move into the fun calculus portion in a few weeks.
History of Unix in Academia
Types of Mathematics Software
Basic Calculators
Native Calc
Emulated (TI85, HP, Casio)
Plotting Software
GnuPLOT
Symbolic Mathematics
MuPAD
Octave
Mathematica
Statistics
R
GnuPLOT
Not Open Source, only coincidentally related by name to GNU
Is *free*, as in beer
Download from gnuplot website
Can run in batch or interactive mode
Batch mode very useful for autogeneration of graphs
Interactive mode useful to see how changes affect graph
E.g., vary the slope, coefficients, x/y offset
First plots
A line!
Quadratics
Zooming in and out
Change grid density
3D plots
The splot command
Hidden line removal
Extras
Changing the default terminal
Setting output file
Importing data from file
Applications
Graphing system load
MuPAD
Solving linear equations
Solving quadratics
Finding the derivate
Computing integrals
Octave
Defining a matrix
Computing determinants
Solving systems of equations
R
Basic statistics
mean, median, etc..
Regression
Pretty graphic demo