Recent content by maverick6664

  1. M

    Why Isn't x^2-1 Divisible by m?

    Thank you! I've got the idea. -Tetsuji
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    Why Isn't x^2-1 Divisible by m?

    Thank you for your reply. r is a primitive root for m. Sorry I wrote "primitive factor" because I didn't know the math nomenclature (I'm Japanese in Japan). This is a Japanese book for preparation for IMO. I'm too old for IMO, but just interested in it and reading. My 1st daughter was...
  3. M

    Why Isn't x^2-1 Divisible by m?

    I have a question; Let m have a prime factor p \equiv 1 (mod 4). Then Euler function \varphi(m) is divisible by 4. Let x = r^{\varphi(m)}, then m|(x^4-1) and x^4-1=(x^2-1)(x^2+1). As gcd(x^2-1,x^2+1)|2, either x^2-1 or x^2+1 is divisible by m. My book says here because of the nature of a...
  4. M

    Anyone prove Fourier representation of the Coulomb potential

    I've seen the Fourier representation of the Coulomb potential is -\frac {Ze} {|\mathbf{x}|} = -Ze 4\pi \int \frac {d^3q} {(2\pi)^3} \frac {1} { |\mathbf{q}|^2} e^{i\mathbf{q}\cdot\mathbf{x}} Will anyone show me how to prove it? (yes, it's the Coulomb potential around an atomic nucleus.)...
  5. M

    Anyone knows website about vector calculus

    I want vector calculus formulae tables, such as \mathbi{a}\times(\mathbi{b}\times\mathbi{c}) = \mathbi{b}(\mathbi{a} \cdot \mathbi{c} ) - \mathbi{c} (\mathbi{a}\cdot \mathbi{b}) and \nabla \cdot (\mathbi{a} \times \mathbi{b}) = \mathbi{b} \cdot (\nabla \times \mathbi{a}) - \mathbi{a} \cdot...
  6. M

    Which notation for pion(0) makeup is correct?

    Thank you for the reply. I don't understand exactly what you mean right now (why ispin doublet for the antiquarks is (\overline u,-\overline d). In my understanding, it's (\overline u, \overline d) and it must make difference), but I'll proceed keeping it in mind, because I don't have a book...
  7. M

    Which notation for pion(0) makeup is correct?

    In my book (Greiner's Quantum Mechanics, vol2, symmetries) says after calculation with Clebsch-Gordan coefficients, |\pi^0\rangle = \frac 1 2 (u\uparrow \overline{u} \downarrow + d\uparrow \overline{d} \downarrow - u\downarrow \overline{u} \uparrow - d\downarrow \overline{d} \uparrow ), And I...
  8. M

    How Do You Calculate Forces on a Banked Curve with Friction for a Race Car?

    Question c and d are quite separate ones, and you can answer quickly 0, because in question a you (are supposed to) have got the right radius with which the car won't slip outside or inside regardless of friction. So questions c and d are given to tell you when friction comes in or does not...I...
  9. M

    Solve e^x cos(x) Intigration Problem

    Easier way is (as others say above) put S(x) = \int e^x \cos x dx = e^x \sin x - \int e^x \sin x dx Now \int e^x \sin x dx = -e^x \cos x +\int e^x \cos x dx Inserting this into the first formula, S(x) = e^x \sin x + e^x \cos x - S(x) and we have S(x)=\frac {e^x} 2 (\sin x + \cos x)
  10. M

    Finding region bounded by curves

    It's just \int_0^1 (x+1-e^{-x}) dx = (\frac 1 2 x^2 + x + e^{-x})\vert_0^1 = 1/2+e^{-1}
  11. M

    Best Software for Drawing Graphics on a Computer for LaTeX Documents?

    I use scilab and octave on Linux. They are not only graphics plotting software, but calculation software similar to MATLAB. And they can be compiled with Intel compilers for faster speed.
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    Calculating Potential of a Hoop in Electromagnetism

    My calculation for potential is (as the question requests :)) d \phi = \frac {2\pi a^2 \sigma \sin \theta} x d \theta so it follows that: \phi = \int_0^\pi \frac {2 \pi a^2 \sigma \sin \theta} x d \theta = \int_0^\pi 2\pi a^2 \sigma (r^2+a^2 -2ar \cos \theta)^{-1/2} \sin \theta d \theta =...
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    Calculating Potential of a Hoop in Electromagnetism

    Yeah! If you calculate potential, you don't have to consider \cos \angle QPO, so it's much shorter and easier! This cosine part makes the calculation complicated, because of this part, partial integral is necessary.
  14. M

    Calculating Potential of a Hoop in Electromagnetism

    oh yeah, it says calculate potential first! lol.
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