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Math Help - Evaluation of Cos(2/3+i2)

  1. #1
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    Evaluation of Cos(2/3+i2)

    Ok basically I need to:

    Express cos(\frac{2}{3}+i2) in the form x+iy

    I've done the following:

    cos(\frac{2}{3}+i2) = cos(\frac{2}{3})cosh(2)-isin(\frac{2}{3})sinh2
    =0.7859 X 3.7622 - i(0.6184 X 3.6269)
    = 2.9567-i(2.249)

    Is this the correct answer? My professor has 0.759567 + i(2.8503) as the answer?
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  2. #2
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    Re: Evaluation of Cos(2/3+i2)

    Quote Originally Posted by Umair View Post
    Ok basically I need to:

    Express cos(\frac{2}{3}+i2) in the form x+iy

    I've done the following:

    cos(\frac{2}{3}+i2) = cos(\frac{2}{3})cosh(2)-isin(\frac{2}{3})sinh2
    =0.7859 X 3.7622 - i(0.6184 X 3.6269)
    = 2.9567-i(2.249)

    Is this the correct answer? My professor has 0.759567 + i(2.8503) as the answer?
    Cos[(2/3) + 2i] - Wolfram|Alpha
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  3. #3
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    Re: Evaluation of Cos(2/3+i2)

    ^l0lwut? urm thx...I think i'm right then lol
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  4. #4
    MHF Contributor Siron's Avatar
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    Re: Evaluation of Cos(2/3+i2)

    According to wolphram alpha it looks you're right.
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