<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>Jackson as a useful book? Its a classic to be sure, but I can count on the fingers of one hand the number of times I have used it to solve a work-related problem. I think of it more as a "rite of passage book". Waynep.s. A good friend of mine who took E&M after me had a professor who thought he whould be cute and make a minor change in a Jackson problem and assign it for a take home test. He ended up with an insoluable problem that kept most of them awake for most of the weekend. <br />Posted by drwayne</DIV></p><p>I still think Jackson is useful, primarily to refresh one's memory. On the other hand I must admit that I can count on one hand the number of time that I have found the direct solution to any work-related problem layed out in any book. In fact I don't think I would use up nearly all of the fingers on that hand. I generally had to work them out myself.</p><p>Changing problem "a little bit" is pretty dangerous. E&M problems like other problems involving partial differential equations are generally only solvable by hand in closed form when there are symmetries to be exploited. Take away the symmetries and you find yourself having to rely on approximations and numerical solutions. </p><p>The "stealth fighter" you may recall has lots of facets and funny-looking flat surfaces.It looks like it can barely fly -- pretty close to the truth. There is a reason for the strange appearance, and it is not that it is optimal for stealth. The reason for the faceted surfaces is that at the time the plane was designed it was designed for stealth, using a good deal of numerical simulation to evaluate its radar signature. The computer codes at the time could not handle curved surfaces, so the design was compromised in order to make the analysis feasible. The B2 was designed later, after the codes had improved and it is rather aerodynamic.</p><p>The situation with fluid dynamics is even worse. The Navier-Stokes equation is truly difficult to work with. It is in fact the subject of one of the prizes being offered by the Clay Institute.</p><p> </p> <div class="Discussion_UserSignature"> </div>