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manishsatywali Group Title

how to find projection of conical surface lying along z axis on the xy plane ?????????????

  • one year ago
  • one year ago

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  1. jtvatsim Group Title
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    Think of shining a light down the z axis. If you have a cone, and shine a light on the very top, what kind of shadow will it cast? A circle. So the projection of a conical surface lying along the z axis is a circle on the xy plane (assuming you mean that the tip of the cone is on the z axis).

    • one year ago
  2. manishsatywali Group Title
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    |dw:1360306137675:dw|

    • one year ago
  3. jtvatsim Group Title
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    Yep, that will be a circle shadow :)

    • one year ago
  4. manishsatywali Group Title
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    i m okk.with circle but want to know that if |dw:1360306291929:dw|

    • one year ago
  5. manishsatywali Group Title
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    |dw:1360306412506:dw|

    • one year ago
  6. manishsatywali Group Title
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    @jtvatsim help plss

    • one year ago
  7. manishsatywali Group Title
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    @hartnn help..........

    • one year ago
  8. jtvatsim Group Title
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    wow... not sure on that part... sorry :( anyone else got ideas?

    • one year ago
  9. manishsatywali Group Title
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    basically i m working on conversion of cartesian to spherical coordinates????????????

    • one year ago
  10. manishsatywali Group Title
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    @saifoo.khan help plss

    • one year ago
  11. manishsatywali Group Title
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    @Ashleyisakitty help plss...........

    • one year ago
  12. manishsatywali Group Title
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    any idea @Ashleyisakitty

    • one year ago
  13. manishsatywali Group Title
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    @jim_thompson5910 ,@Luis_Rivera ......pls help any1

    • one year ago
  14. manishsatywali Group Title
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    @rebeccaskell94 help

    • one year ago
  15. khoala4pham Group Title
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    I'm sorry, what is the dot product of?

    • one year ago
  16. manishsatywali Group Title
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    |dw:1360307330028:dw|

    • one year ago
  17. khoala4pham Group Title
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    I can't understand what it says do you mind typing it out?

    • one year ago
  18. manishsatywali Group Title
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    THETA is a constant and represents equation of cone in spherical coordinates

    • one year ago
  19. khoala4pham Group Title
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    Are you asking for the projection of theta onto the x axis? There is no straightforward solution. in spherical polar, the conversion is x = (rho)*cos(theta)sin(phi). however, the fact that you have a unit vector for theta is confusing. The two are independent of each other. It's like comparing apples and oranges.

    • one year ago
  20. khoala4pham Group Title
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    For a "normal cone" the equation is typically theta = pi/4 if that helps

    • one year ago
  21. manishsatywali Group Title
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    plsss...........w8 i m clearing what i intended to ask @khoala4pham

    • one year ago
  22. manishsatywali Group Title
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    |dw:1360307890501:dw|

    • one year ago
  23. manishsatywali Group Title
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    |dw:1360308115075:dw|

    • one year ago
  24. manishsatywali Group Title
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    while finding A(thetha) i m getting |dw:1360308301921:dw|

    • one year ago
  25. manishsatywali Group Title
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    @robtobey help

    • one year ago
  26. khoala4pham Group Title
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    Please use the equations. I have no idea what these symbols mean. If your question is what is the unit vector of theta dotted with that of x, then I have no idea. The conversion of x to theta or vice versa involves a Jacobian which is computationally tedious. They are of different coordinate systems!! The mapping of x,y,z to r,theta,phi is not straightforward. It's not simply asking what i dot j is or what j dot k is. Honestly, you are asking for help but what is the question asking? The projection of a cone onto the xy plane is any number of circles. They are inherently level curves of the cone.

    • one year ago
  27. manishsatywali Group Title
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    see i m asking if we have to convert cartesian to spherical coordinates we need to find the A(theta) FR THATwe need projection of cone first over over the xy plane ..then its projection along x and y axis to get dot product with unit vector along x and y axis respectively.

    • one year ago
  28. manishsatywali Group Title
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    see the case of finding A(r) it is simple the projection of line with distance r from origin on xy plane frst........that is |dw:1360308936766:dw|

    • one year ago
  29. manishsatywali Group Title
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    @Hero plsssssssssssssssssssss answer

    • one year ago
  30. khoala4pham Group Title
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    I don't even know what you are getting at. if you are looking for the conversion of cartesian to spherica;, x= rho*sin(phi)*cos(theta) y = rho*sin(phi)*sin(theta) z = rho*cos(phi) But the rest of your information is extremely lacking. This is some random cone in random space that can be projected in ANY way imaginable. If my light source is sufficiently far away, your projection is huge; if it's close, miniscule. There is no way to pinpoint one. You HAVE to specify at least a level curve or SOME CHARACTERISTIC of the cone. The equation theta = 1, theta = 2, theta = 3 are all cones. You are overcomplicating this problem if I am to understand correctly. Project it onto x and then onto y and take the vector sum. But you can't use spherical and cartesian at the same time! It's like calculating velocity in miles per hour and getting distance in kilometers without converting...it doesn't work.

    • one year ago
  31. manishsatywali Group Title
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    but in my book answers are :|dw:1360309534965:dw|.................anyway thanks fr d help

    • one year ago
  32. khoala4pham Group Title
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    I'd dare say that is incorrect. for the first unit vector, by virtue of being a unit vector, it has to be <1,0,0>, <0,1,0>, <0,0,1>. Ax and Ay (if this is your notation) is <1,0,0> and <0,1,0>. One of those two dot products MUST equal zero.

    • one year ago
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