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Math Help - rectangular conversions?

  1. #1
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    rectangular conversions?

    hi sorry about this but i cant remeber how to convert these.

    how does this :
    1.5, -60degrees +2.3, -18degrees

    become:

    (0.75 -j1.3) +( 2.19 -j0.71)?

    i know you do 1.5 x cos -60 = 0.75 and cos 2.3 x -18 = 2.19 but how do i get the j numbers?

    any help appreciated hope i posted it correctly!
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  2. #2
    MHF Contributor Unknown008's Avatar
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    By using sine instead of cos

    If you want to picture it, you have a line of length 1.5 units at -60 degrees from the x-axis.

    What are the horizontal and vectors to go to that position? You draw a horizontal and a vertcial line, such that you get a right angled triangle, with the length of the line as the hypotenuse and the horizontal and vertical as adjacent and opposite sides.
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  3. #3
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    so thats 1.5cos60 and 1.5sin 60? seem to remember now.please confirm i am getting there!
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  4. #4
    MHF Contributor Unknown008's Avatar
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    Don't forget your negative, but yes, that is the concept. You have the values, so you can check by yourself
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