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Math Help - Find a Cartesian co-ord when you have a start co-ord, distance and angle

  1. #1
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    Find a Cartesian co-ord when you have a start co-ord, distance and angle

    Hi guys,

    I am trying to determine a co-ordinate, when I have a start co-ordinate, a distance to the new co-ordinate and the angle. (using a 2D Cartesian system).

    I believe the answer is something like the following; however it does not seem to give me the right answer.

    x2 = x1 + cos(angle) * distance
    y2 = y1 + sin(angle) * distance

    any help will be greatly appreciated!

    Thanks, Mike
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  2. #2
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    arctan(y/x)=angle

    if the start co-ordinate is (x1,y1) then distance =sqrt((x1-x)^2+(y1-y)^2)
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  3. #3
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    Thanks poirot

    Though I do not think I explained what I need fully.

    I have the following:

    1) a start co-ord x1,y1
    2) distance to new co-ord (x2,y2)
    3) angle/direction to new co-ord (x2,y2)

    and I need to work out the what the new co-ordinate (x2,y2) will be.

    Any takers? thanks
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  4. #4
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    I have explained. I have used (x,y) as the new co-ordinates. You have 2 equations involving x and y. Solve
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  5. #5
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    Quote Originally Posted by mxdatamike View Post
    I am trying to determine a co-ordinate, when I have a start co-ordinate, a distance to the new co-ordinate and the angle. (using a 2D Cartesian system).
    x2 = x1 + cos(angle) * distance
    y2 = y1 + sin(angle) * distance
    It is not at all clear what transformation you have described.
    Are you rotating about a point, which point?
    Then are you elongating the vector?
    What do you think multiplying the cosine by the distance does?

    I think that you should try giving a detailed description of the transformation.
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