Recent content by Jadehaan

  1. J

    Proving an equation involving 4 real numbers

    Homework Statement This is the question followed my my attempt at the solution: Just wondering if this looks right? Thanks for any and all feedback, Jim
  2. J

    My proof involving Pythagorean’s Theorem

    Thanks for the help snipez90 and Dick. I redid the problem. This is my original: And this is my new proof:
  3. J

    My proof involving Pythagorean’s Theorem

    Homework Statement Let a, b, and c be lengths of sides of triangle T, where a ≤ b ≤ c. Prove that if T is a right triangle, then (abc)2=(c6-a6-b6)/3 Homework Equations If T is a right triangle, then Pythagorean’s Theorem states: The sum of the squares of the lengths of the...
  4. J

    Mapping the Unit Ball to a Sphere of Radius c

    Right, I misdefined the unit ball in my last two posts. Now the unit ball should be defined by x^{2}_{1}+x^{2}_{2}+x^{2}_{3}=1 Using the result for y_{1} if x_{1} is on the surface of the ball, x_{1}=1 and the other x's must equal 0. This implies that y_{1}=c. And if x_{1} grows large, the...
  5. J

    Mapping the Unit Ball to a Sphere of Radius c

    y_{1}=\frac{cx_1}{x_1^2+x_2^2+x_3^2} If x is on the unit ball, x=\sqrt{1-y^2} How do x_1, x_2, x_3 play a part?
  6. J

    Change of Variables of f(x+y) (In Multiple Integrals)

    Homework Statement The problem is as follows: Let T be the triangle with vertices (0,1), (1,0), (0,0). Compute the integral \int\int\frac{sin^{2}(x+y)}{(x+y)} dxdy by making an appropriate change of variables. (Hint: check #24 Section 15.9) Homework Equations Problem 24 in 15.9 of...
  7. J

    Moment of Inertia about the line x=y

    Yep, thanks so much Dick.
  8. J

    Moment of Inertia about the line x=y

    I see. I was using the wrong distance formula. So using the formula for the distance between a point (m,n) and a line Ax+By+c=0 the distance is r= |Am+Bn+C|/ sqrt(A2+B2) Using the point (x,y) and the line x-y=0 I calculated the distance r=|x-y|/sqrt(2) Does this sound correct?
  9. J

    Mapping the Unit Ball to a Sphere of Radius c

    Homework Statement Let B be the outside of the unit ball centered at the origin, and let c be a non-zero constant. Consider the mapping where k=1,2,3. Find the image of the set B under the mapping. (Hint: consider the norm of (y1, y2, y3)) Homework Equations The unit ball would be 2...
  10. J

    Moment of Inertia about the line x=y

    Thanks for your help. You were right, I mistyped the formula for the moment about the x axis. Using points (x,y) and (y,x) I calculated r2=2x2-4xy+2y2 So the formula would be the integral of this multiplied by rho dA.
  11. J

    Moment of Inertia about the line x=y

    Homework Statement Let \Omega represent a two dimensional material region who density is given by \rho(x,y). Establish an integral formula for the moment of inertia of the material region about the line y=x. Homework Equations The moment of inertia about the x axis...
  12. J

    Limit as 9x,y) approaches (0,0)

    Homework Statement Justify if the limit of the following function exists as (x,y) approaches (0,0). If it exists find the limit using the squeezing technique. f(x,y)=(exy-1)/(x2+y2) Homework Equations The Attempt at a Solution I found the limit of f(x,0) to approach 0 I found...
  13. J

    Range of the parameter of sphere intersecting with a plane

    Homework Statement Find the range of the parameter d for which the intersection of the sphere x2+y2+z2=1 and the plane x+y+z=d is non-empty. Homework Equations Cartesian coordinates of a sphere: x=rcos\thetasin\phi y=rsin\thetasin\phi z=rcos\phi r=1 The Attempt at a Solution...
  14. J

    Photon Energies of Hydrogen in the n=6 State

    Ok I see now that there is only 1 photon energy from 6 to 1. Since the Thomson model did not take this into account does that mean there are 0 photon energies for that model?
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