[ale] graphing calculator

[drifter]

Gentle folk,
my brother needs your help.
He is retired navigator for the USN. Now tutoring kids in math in
New Bern, NC, and finds the textbooks (middle school/high school)
the kids are forced to use just about impossible.  From his point of
view he is amazed they can learn any algebra/geometry/trig at all.

So he is struggling to write his own textbook he can give to the teens he 
is working with.  To that end he needs an app (windoze, cough, cough)
that will allow him to input an algebraic equation and get out a graph in
a file format (jpg, etc) that he can then import into the Open Office file
he is creating.

I will take credit on weaning him away from Office. :)

Any thoughts?

Sean