# Search results

1. ### Has anyone ever programmed a computer system to evolve theories?

Perhaps you might enjoy reading/learning about genetic algorithms, or even broader, Evolutionary Algorithms in Computer Science. Are you familiar with these algorithms? Obviously, I'm still not sure how you can define a "theory" to a computer... but its along the lines of what you are talking...
2. ### Is there an easy way to simplify a 3 term squared paranthesis?

I mean... there isn't really any shortcut to this (If thats what you are looking for) You can do (A*B + C*D + E*F)^2 = (A*B + C*D + E*F)*(A*B + C*D + E*F) and just multiply it out term by term.. or you can let a = AB+CD, and b = EF and use the general form for (a+b)^2 so.. (AB + CD)^2...
3. ### Is there an easy way to simplify a 3 term squared paranthesis?

what are A, B, C, D, and E? Real or complex? I'm not entirely sure what you mean by "simplify" because it already seems to be in simplified form. Did you mean expand? If you meant expand.. Then use the general {(a +b)}^2 = a^2 +2ab +b^2 ... let AB+CD =a, and EF = b
4. ### Two boxes on each other

Ok, before I attempt to explain it again.. I'll try to show the flaw in your logic (bear with me here). "The top box cannot have a force higher than 1.715" - this is true "the bottom box has to overcome 2.95 N" - This is not true. Draw your free-body diagram for the lower box, and you will see...
5. ### Graduate Studies - Categorical Logic

CMU!! (there might be some bias to that of course.. :) )
6. ### Can I get into MIT, cal Berkeley or Stanford?

Mit is pretty cut-throat, it will be awesome if you get in. The problem with Berkeley is that their admission rate is about 80% in-state. Thirdly, Stanford is just amazing. Although these are difficult schools to get in, I think you have a shot. You should consider Carnegie Mellon, their CS...
7. ### Basic Vectors Problem

you're welcome. I presume you had no problems?
8. ### Absolute value on both side of equation

ok well... one of the mistakes I see is how you reached the conclusion "3x +2 =3x +2 for all real nobs" well, this isn't true... is it? ex: x= -1. |3(-1)+2(-1)| does not equal (-1)|3(-1)+2|. Break it up like this: { |3x^2 + 2x|= |x||3x+2| = x |3x + 2| } \Rightarrow { |x|=x , for (3x+2)...
9. ### Fun math problem I made up

The level of difficulty of a problem does has nothing to do with how confusing the notation is. It seems like you went out of your way to make this problem as confusing as possible.. its not only confusing, but it has several errors. A genuinely difficult math problem will be difficult...
10. ### Basic FrictionIs this right?

looks good... except for the part 196/1960 = ... well not .2 XD
11. ### How to deal with this Neumann boundary conditions?

It is very likely that they used wolfram alpha, Mathematica, or MATLAB to solve for the two ODE's: F(z) and G(t). You can let u(0,t) = h(t). Then once u(z,t) is solved for, its not hard to find something like that. But again, I would need to see what their PDE was, and the boundary conditions. I...
12. ### Two boxes on each other

I'm guessing that should be 3.43m/s^2? Rounding error perhaps? How did you get this? Now ma_{net}= F - F_k -F_s , remember you are applying the force on the lower box, so you should know what the value of m is from that. **edit: Ok i see how you got 3.10. You did 4.655/1.5; however, you are...
13. ### Fun math problem I made up

would you mind explaining where the integral comes from and what is that awkward symbol, that sort of looks like the Summation Sign (Sigma)? Moreover, what is f? In general, I can't make any sense of what's going on
14. ### SHM Problem

You use your initial conditions to find the coefficients A and B. You have the correct value for A, and we see that B is 0. Hence, this X(T)=Asin(wt) satisfies the initial condition X(0)=0. We know X(0)=0 because the problem says the spring is relaxed. Look at it this way... If it had said the...
15. ### Two boxes on each other

Ah, absolutely 4.655 isn't the maximum. I should really be careful when I look at these late at night.. *angry face* :/. F needs to be maximized such that the top box doesn't fall off. The maximum acceleration so that the top box doesn't fall of is: 1.715 N = 0.5 kg * a, then use that a for...
16. ### Two boxes on each other

I think thats why he/she added the 1.715 N, this is so that two boxes move together with same velocity AND acceleration
17. ### Two boxes on each other

yup, assuming you did your math right.
18. ### Basic Vectors Problem

so try drawing a diagram of this. Break this up into X, and Y components (do you know what components are?) So huck is moving 1.0 m/s in the +y direction and 2.7 m/s in the +x direction due to the river. So how do we add vectors? we use the Pythagorean theorem to find the magnitude (although you...
19. ### Generalization of infinite product problem

ah so sorry. I was accidentally taking the SUM. In that case, it DOES converges to 0. Perhaps, F needs to be clearly defined.
20. ### Generalization of infinite product problem

This isn't true. As n gets larger, the partial products approach 1. Ya, don't make that assumption. Just assume what's given: f(m+n)>f(m). Use induction to prove the original claim. Shouldn't be too difficult.
21. ### Generalization of infinite product problem

I have never heard or seen it being used like that. I thought the general definition of convergence implied that the limit approached a finite value. But of course, I do understand what you are saying and it makes sense.
22. ### How to deal with this Neumann boundary conditions?

hey daz71, Have you made any progress? So, obviously I'm getting stuck on the bounds you imposed. I'm guessing that you reached those bounds through experimentation, which is why I am not questioning it. Moreover, I don't have much experience with experimentation. How sure are you of the second...
23. ### Maximum principle

Check it out: http://www.math.ucsb.edu/~grigoryan/124A/lecs/lec8.pdf It's great. It has the proof of the maximum principle (its weaker form) in detail. I think you should find it useful. Honestly, there are plenty of problems online and in textbooks (you can use google books). Here is one I...

great!
25. ### Maximum principle

do you want a real-life example or an actual math problem that uses the maximum principle?
26. ### How to deal with this Neumann boundary conditions?

Ignore what i got for h(z,t), it doesn't work for the given PDE. Vt does not equal to (alpha)*Vzz. However, its still important to realize u(z,t) is probably not unique, and uniqueness is important. Hm its about 2:15 am in my time. I'm really tired and sleepy, but I have a feeling you will...
27. ### How to deal with this Neumann boundary conditions?

Understand that when you make up your own problem (what is this for btw? for a research? or just for fun?) you have to check for uniqueness. We can't assume uniqueness for u, this would have to be proven (and I highly doubt its unique). Hence, h(z,t) is not unique either, and you might have...
28. ### How to deal with this Neumann boundary conditions?

well yes, i didn't think this was a homework. Normally for non-trivial homeworks you would be given a hint. You set this yourself?! Then you should be able to answer my questions about "u"? So, obviously the "u" can't be u(z,t) for the first boundary condition... you understand that right?
29. ### How to deal with this Neumann boundary conditions?

ahh ok. So, i'll just tell you up front. I'm still a second year undergrad student. Obviously, I'm NOTHING compared to some of the people here. So please excuse me if I have bit of a difficulty with it. Nonetheless, this looks like an interesting problem! Let's attempt it together. Ok, going...
30. ### How to deal with this Neumann boundary conditions?

ahh, no, no its not your fault. It's mine. I was a bit confused because I thought it was a form of neuman boundary. In that case, I'm lost. I'll try to figure it out. Sorry I couldn't be of more help. It doesn't make sense how Uz(0,t)= K(U(z,t)- Ub) on the boundary (excuse my capitalization of...