Recent content by rakeru

  1. rakeru

    Finding Constants to Solution Given 2nd Order, Nonlinear DE

    Alright, I ended up with A=+/- 1 and B=1/sqrt(2).
  2. rakeru

    Finding Constants to Solution Given 2nd Order, Nonlinear DE

    Ahhh yes. I understand! Thank you very much :)
  3. rakeru

    Finding Constants to Solution Given 2nd Order, Nonlinear DE

    I keep getting that phi is zero.
  4. rakeru

    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. rakeru

    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. rakeru

    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 not...
  7. rakeru

    Ethical Considerations in Requesting and Writing Recommendation Letters

    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. rakeru

    Undergrad 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. rakeru

    Undergrad 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...
    • rakeru
    • Thread
    • Derivative Differential Differential equation Differential equations Function
    • Replies: 6
    • Forum: Differential Equations
  10. rakeru

    Rolling Ball and Proportionality Between Distance and Time

    Thanks a lot. I didn't know it was so complicated. Thanks again.
  11. rakeru

    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^2The Attempt at a...
  12. rakeru

    Two values for m for which a line is tangent to a parabola

    Ouuuu interesting. Thank you :)
  13. rakeru

    Two values for m for which a line is tangent to a parabola

    Thanks!
  14. rakeru

    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. rakeru

    Schools Which French Universities Have Strong Physics Departments?

    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...