The best definition is an obtuse one ...Applied mathematics is essentially indistinguishable from theoretical physics.Applied mathematics uses the wide precepts, theories and teachings of all areas of math to examine potentially reallife problems. 'RealLife' could mean the Big Bang, black holes, spherical packing, epidemiology, gravitation, some esoteric phenomenon of your shoelaces, etc..Applied mathematics differs from theoretical math in that theoretical math is concerned with problems that do not necessarily have any application to real life. A theoretical math problem might be a topology proof, a primenumber proof, etc.. While theoretical math can be applied to reallife problems, that is usually a secondary result, rather than a primary goal. The primary goal of applied math, on the other hand, is to use math to explain physical processes.
