Marsden
and Tromba, "Vector Calculus", 5th edition:
The website includes an "Internet Supplement": a pdf
file (2628KB) containing
some more technical proofs, some interesting applications, and
a sample examination with complete solutions.
http://bcs.whfreeman.com/marsdenvc5e/
3D-XplorMath
is a mathematical visualization program for Macintosh
computers running version 9 or later of MacOS. It can be used
to explore many interesting mathematical objects, ranging from
planar and space curves to polyhedra and surfaces to ordinary
and partial differential equations, and fractals:
http://rsp.math.brandeis.edu/3D-XplorMath/index.html
3D-XplorMath
Galleries
This
contains pictures of many interesting surfaces produced by
Richard Palais's program 3D-XplorMath:
http://rsp.math.brandeis.edu/3D-XplorMath/TopLevel/gallery.html
Web
Links for Minimal Surfaces