Recent content by longbusy

  1. L

    Real World Applications of Cubic Equations

    Actually, I do not have examples, that is my purpose here. I am sure fluid/air flow or other physical examples can be modeled according to these polynomial equations.
  2. L

    QM Integral and Online Integral Tables

    Oops, sorry, A is a constant. It is not dependent upon x. I could have just left that out.
  3. L

    Real World Applications of Cubic Equations

    I've been kicking myself trying to think of a few real world applications of cubic equations (and x^4 quintive?). Can anyone give me a few examples? Thanks, Jeremy
  4. L

    QM Integral and Online Integral Tables

    Hello, I am hung up on an integral from Quantum Mechanics. I searched on Yahoo and Google for online integral tables, but failed to discover anything beyond very basic tables. The integral is as follows: \int_{-\infty}^{\infty} \(A*e^{-(x-a)^2} dx Are there any decent online integral...
  5. L

    Carnot Cycle and Line Integrals

    I have to corellate the Carnot cycle with line integrals. This makes sense to me as line integrals can be used to find the work done by a vector field on an object traveling along a certain path. The Carnot cycle places a limit on the efficiency of an engine cycle. My question, how could I...
  6. L

    Portland!Where Are You From? Oregon Members and Beyond

    Born in Florida, lived all over the South, back in Florida, still learning to (re)count
  7. L

    How Old are You? - Revisiting an Old PFs Thread

    19 years 133 days + some unassorted seconds...
  8. L

    Trouble converting Cartesian to Polar

    Thanks! I am working on a lot more of these problems now. Better safe than sorry. I just cannot understand why only Odd answers are given in supplemental answer books. If professors do collect homework, work has to be shown... Just doesn't make sense. :) Thanks again!
  9. L

    Trouble converting Cartesian to Polar

    Mixing up Spherical with Cylindrical for some reason. So it should remian r^2 + z^2 = 9?
  10. L

    Trouble converting Cartesian to Polar

    I meant octants, not quadrants. Sorry! That explains the 8. In cyclindrical coordinates, I got the following for x^2 + y^2 + z^2 = 9: So, r goes from 1 to 3 - 3cos(theta) right? Thanks a lot for your help, I know I am being a bit dense.
  11. L

    Trouble converting Cartesian to Polar

    Well, it's in polar coordinates, not cylindrical... But I assume those are correct. What I calculated: r^2 = 9 - 9cos^2(theta) -or- r = 3 - 3cos(theta) Now, the book claims that the bounds are: 8Int[0, pi/2]Int[1,3]...(dr)(d(theta)) I understand the first bounds (eight quadrants...
  12. L

    Trouble converting Cartesian to Polar

    I am mainly having trouble figuring out the bounds. I can draw the pictures and see them. I cannot figure out the bounds. That is what is holding me up.
  13. L

    Trouble converting Cartesian to Polar

    Hurkyl, thanks, I am working through some topics you listed now. I did well in Calc 2 with the substitution. It is just stuff like the following: "Use a double integral in polar coordinates to find the volume of the solid that is described." x^2 + y^2 + z^2 = 9 (inside) x^2 + y^2 = 1...
  14. L

    Trouble converting Cartesian to Polar

    Actually, the substitution part is what we're working on right now. That is why I asked the question. It's killing me. :) I'll just keep trudging. Thanks!
  15. L

    Trouble converting Cartesian to Polar

    Well, it is not really hard to convert them. My main problem is thinking in Polar coordinates. Cartesian coordinates are really easy to think about for me (after how many years of experience) but then I get to Calc 3 and I hit a brick wall. Does anyone have some insight on how to get past...
Back
Top