# Recent content by rakeru

1. ### Finding Constants to Solution Given 2nd Order, Nonlinear DE

Alright, I ended up with A=+/- 1 and B=1/sqrt(2).
2. ### Finding Constants to Solution Given 2nd Order, Nonlinear DE

Ahhh yes. I understand! Thank you very much :)
3. ### Finding Constants to Solution Given 2nd Order, Nonlinear DE

I keep getting that phi is zero.
4. ### Finding Constants to Solution Given 2nd Order, Nonlinear DE

The second derivative is phi''=-2AB^2tanh(Bx)sech^2(Bx)= -2AB^2tanh(Bx)+2AB^2tanh^3(Bx) and so tanh(Bx)[2AB^2-A]+tanh^3(Bx)[-2AB^2+A^3]=0
5. ### Finding Constants to Solution Given 2nd Order, Nonlinear DE

d^2phi/dx^2= -2AB^2tanh(Bx), correct? Now I have gotten the equation tanh(Bx)[2AB^2-A+A^3tanh^2(Bx)]=0 I set 2AB^2-A+A^3tanh^2(Bx)=0 tanh(Bx)= sqrt[2B-1]/A But now what? Was I supposed to change the tanh^2(Bx) into 1-sech^2(Bx)?
6. ### Finding Constants to Solution Given 2nd Order, Nonlinear DE

Homework Statement Okay, here's the deal: I have been given a second order nonlinear differential equation, and I have also been given the general solution with constants A and B. I am supposed to find the constants A and B. The solution represents a fermion at rest, since the solution does...
7. ### Recommendation Moral Dilemma

Hello! I am wondering if anyone can help me decide what to do about this problem. I'm at a college majoring in physics, and I'm almost done with my two years. I'm applying to different universities,and I have a professor that wishes to write me a recommendation for when I transfer. He asked me...
8. ### Is the Derivative of a Function a Differential Equation?

I am talking about first order ones.. I don't know how to solve second order ones.
9. ### Is the Derivative of a Function a Differential Equation?

Is the derivative of a function a differential equation? I guess it would be because it involves a derivative, right? Would the solution to the equation just be the original function? Is solving a differential equation just another way of integrating? Like with finding solutions of separable...
10. ### Rolling Ball and Proportionality Between Distance and Time

Thanks a lot. I didn't know it was so complicated. Thanks again.
11. ### Rolling Ball and Proportionality Between Distance and Time

Homework Statement A ball starts from rest and rolls down a hill with uniform acceleration, traveling 130m during the second 6.0s of its motion. How far did it roll during the first 6.0s of motion? Homework Equations I guess: v=v(0)+at v^2=v(0)^2+2ay x=x(0)+v(0)t+0.5at^2 The Attempt at...
12. ### Two values for m for which a line is tangent to a parabola

Ouuuu interesting. Thank you :)

Thanks!
14. ### Two values for m for which a line is tangent to a parabola

Homework Statement Hi! I am doing some problems to practice for a math competition, and I'm wondering if I did this correctly. I don't really have an answer sheet, so I have no way of knowing whether I'm right. If you would please review it, that would be cool! It reads: There are...
15. ### Schools French Universities For Physics

Hello! I'm wondering if anyone knows any universities in France that have a great physics department. I'm currently in my second year of college getting my associates degree, and I'm looking at options in France for my bachelors. My French professor is always talking about French...