Recent content by MacNCheese

Isn't it? Then how do we derive such an expression? Thanks, that helps.

Well if you look at something like center of mass, it's mentioned as (in wikipedia) \frac {\sum m_i r_i} {\sum m_i} for discrete particles and \frac {1} {M} \int r dm for continuous distribution. There's no 'delta' anywhere.

Factorization means using recursion (or maybe there's a faster way? idk) to decompose the given number into prime factors, i.e. with their powers. Since you'd have to keep track of how many times it can be divided by each prime factor, I'd say it'd take longer than O(n). What you're doing is...

When converting a summation of the form \sum x_i y_i to integration, how do we know if it's \int x dy or \int y dx At first I thought they're equivalent but obviously that's only true for a linear function with no constant offset. I kind of see integration as a better...

Wow, thanks a bunch. That helped clear my concept of entropy a lot. Does this mean that if I'm given the initial and final volumes and the moles of the gas, the change in entropy will be nR * ln(V_2/V_1)? Also, is the change in entropy of the surroundings zero? EDIT: Why can't I use an...

But isn't entropy change equal to heat supplied divided by the temperature?

I searched in the fora, and I did find https://www.physicsforums.com/showthread.php?t=292278" asking pretty much the same thing. Internal energy change and work done are zero, so no heat is absorbed. Thus entropy is zero, hence it isn't spontaneous. What am I doing wrong? Could you also...