Recent content by aperception

Anyone? I know there are lots of Boas lovers on here

Integrating Factors for ODEs (Question from Boas) Find an integrating factor by inspection to make the below differential equation exact. (y^2-xy)dx+(x^2+xy)dy=0 I've been inspecting, but I'm not seeing it! Is there a way to analyze this in my head that will lead me more easily to the...

I realize that this thread is 5 years old, but I spent a bit of time thinking about it, and feel that I can add a little more physical clarity for anyone who searches and finds this thread. I will discuss a pnp transistor with geometry as per figure 5.6 in Sze (attached). In the forward active...

OK thanks for your reply, I guess I will take your word for it (that there can't be both J and K in a conductor) until I get around to studying E&M at graduate level.

Sorry to revive this thread again, but I'm puzzling over it myself, and I'm still not convinced by any of the answers to the OP question - what exactly does Griffiths mean by "this would require an infinite electric field at the boundary"? What are the relevant equations to see that this is...

that's perfect, thank you!

Ah, thank you! I understand!

Does anybody know much about how this works? I can't understand why it doesn't give me an answer for definite integrals sometimes... e.g. in Matlab R2011a: syms x a; int(x/sqrt(x^2+a^2)) gives the answer (a^2 + x^2)^(1/2) as expected. But int(x/sqrt(x^2+a^2),0,10) gives - Warning...

That is very clever, it worked great thank you!

Hi guys, would appreciate any help with this problem. It's from a graduate school entrance examination which I am practicing. problem statement When n is a natural number, the indefinite integral I_n is defined as I_n=\int\frac{1}{(x^2+a^2)^n}dx Here, a is a constant real number, and...

http://ocw.mit.edu/OcwWeb/Materials-Science-and-Engineering/index.htm" was quite useful... and there's a reference in one of the modules to a book called "Roark's Formulas for Stress and Strain" which gives solutions to most of the problems for which analytical solutions exist. From a skim...

I also need to know about a related problem although not for homework... I'm trying to do an order of magnitude calculation for a photoelasticity experiment. If I have a cube/cuboid with a point force applied normal to one of the surfaces in the center and an equal and opposite force applied...