Recent content by superspartan9

Homework Statement Explain why, for an ideal mixture, the mixing entropy is given by ΔSmixing = k ln( Binomial Coefficient ( N, NA ) where N is the total number of molecules and NA is the number of molecules of type A. Use Stirling's Approximation to show that this expression is the same as...

Nevermind. I feel dumb now.

Where did you get your multiplicity of the combined system equation?

Got it! Taking the derivative with respect to a of part c) yields the answer! :D

Another Update: The above equation is correct because it yields the correct value for part c). Now I'm just stuck on d) where it's asking me to differentiate... More later if I figure it out.

Update: Just tried substituting u = a*x^2 into the integral, and it evaluated to -(1/2a)*e^(-a*x^2) I think it's right... but I'm not sure, the substitution worked though because the du = 2ax dx which means we can just throw the constants in there.

Alright, I figured out the first one in class by drawing the graph for x and e^(-ax^2) and realized that the x made the function odd, as you said, and that the integral was then 0 for -inf to inf. I'm going to try and tackle c) and d) because I have no idea where to start on b) with that...

The first one is -inf to inf, second is indefinite, third is 0 to inf, and fourth is 0 to inf.

Homework Statement The integral of (x^n)(e^(-a*x^2)) is easier to evaluate when n is odd. a) Evaluate ∫(x*e^(-a*x^2)*dx) (No computation allowed!) b) Evaluate the indefinite integral of x*e^(-a*x^2), using a simple substitution. c) Evaluate ∫(x*e^(-a*x^2)*dx) [from o to +inf] d)...

Thanks everyone for your responses especially 256bits for his links on the course work and the guide that really helped me figure out how to the do calculations. I managed to get an excel sheet built to help me with the calculations based on the links and some research papers to get values for...

Hey everyone! Thank for the responses! 1) Yes, this chip is a thermoelectric chip absorbing IR off an emitter heated by natural gas. 2) The 1500 K is the temperature the emitter will cause the chamber to heat up to--depending on the convection coefficients I use, I can get the chip temperature...

Hey all, I'm trying to simulate a simple chip-heatsink situation in SolidWorks using their thermal modeling suite. I have found an ideal set of parametric values for the chip to work at a reasonable temperature, but I need to figure out what the convection coefficient means in terms of air flow...

Homework Statement A current I is flowing along the y-axis and a spherical surface with radius 1 m has its center at origin, as in the figure left. A closed contour C is chosen as in the figure, which is a boundary between two semi-sphere surfaces S1 and S2. Based on the...

Actually, I'd probably want to switch the two around to get a positive phase change, right?

[(thickness * n * 2∏) / λ] - ([(3 * thickness * n * 2∏) / λ] + ∏) = 2k∏ ?