I am interested in getting software from the Internet to be able to
do all kinds of calculus and/or differential equations.

It is especially of importance to me to find an equation or make one, plug in
the numbers, turn the crank and get the right answer.

Either calculus or differential equations. Both in one would be best.

John

What kind of calculus? Integral or differential?  Multivariate or
univariate?  Do you want symbolic results or numerical results?

Similarly, what kind of differential equations do you want to handle? 
Partial differential equations or ordinary differential equations? 
Single equations or systems of equations?  Linear equations or
nonlinear equations?  Do you want software that provides analytical
solutions (if they exist) or will numerical solutions suffice?

I use Derive 5, its real powerful

Differential equations--- That shows you what I know. I am just
getting started on some study on the planets, the sun, gravity,
electromagnetism, etc.

I need numbers answers for sure. The other ones I don't know what they
are yet.
Whatever is most used I guess is where I can start.

Thanks for asking for a clarification.

Hi pendleton,
Mathematica (http://www.wolfram.com/) is a favorite tool for college
students.  A free alternative is Maxima
(http://maxima.sourceforge.net/), which contains most of the features
of Mathematica.  Both of them have plenty of algrebraic tools,
including tools to integrate and differentiate expressions.  You have
to spend some time to get used to them though.

Good luck,
secret901-ga

Mathematica, from Wolfram Research, should be able to do this.

http://www.wolfram.com/products/mathematica/index.html

My two cents... check out MLAB by Civilized Software:

[MLAB - Civilized Software]
http://www.civilized.com/

The software comes with several books detailing sample problems solved
as ordinary differential equations or systems, which can be specified
by inputting them on a command line interface in relatively intuitive
fashion.

MLAB can actually turn the problem around and do parameter fitting to
data with ODEs, or solve optimization problems.  It also has an
extensive set of built-in "special functions," which might generically
be defined as solutions to specific second order differential
equations.

If you want to crunch numbers out of ODEs associated with physical
problems, etc. MLAB might be what you want.  It's more symbolic than
the base Matlab (or Octave), and less expansive than Mathematica.

regards, mathtalk-ga

Other possibilities include MAPLE (a competitor of Mathematica, see
http://www.maplesoft.com/) and MathCAD
(http://www.mathcad.com/products/Mathcad.asp), which is primarily a
package for finding numerical solutions, but which includes a subset
of the MAPLE computational engine for duing symbolic manipulations.

The National Institute of Standards and Technology (NIST) maintains a
comprehensive database of mathematical software packages, both
commercial and noncommercial (i.e., public domain and shareware). See
http://gams.nist.gov/  You can browse the database in several ways,
including by the types of math problems the packages are designed to
solve.   This might be a good resource once you get further into your
studies.

Thanks so much to everyone for your valuable and helpful comments.
Good as answers for me. 

5 stars!

God bless you to know and do His will!
John