dsolve(diff(y(t),t)y(t)^2,[y(t)]);
it will solve the differential equation [dy/dt]  y^{2} = 0 . You can find more examples of Maple code on this page. Unfortunately, this frontend apparently stinks on returning graphical output, so the examples of direction fields on that page don't work very well. You'll have to cut and paste them into a real copy of MapleV.
A site called SOS Math at the Univ. of
Texas at El Paso offers pages of material on topics ranging from polynomial long
division, the quadratic formula, and trigonometric identities, to Taylor polynomials,
the CauchyRiemann equations, and Matrix algebra. Dan Sloughter has a web page containing Java programs for visualizing various mathematical concepts. My favorite is one which will draw the Taylor polynomial approximations for y=sin(x) . A site called Karl's Calculus Tutor currently covers most of what would qualify as firstsemester calculus, and some of the second semester, as well. Forget a geometry formula? Check this page at Trinity College. A Javaenabled page for generating Pascal's triangle (or rather, the last two digits of each entry, which is good enough through the 24th line). What's the pattern of the even numbers in the triangle?!
