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Math Help - Trig Ratios: Solve for x when x is between 0 and 360

  1. #1
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    Trig Ratios: Solve for x when x is between 0 and 360

    Solve for x when x is between 0 and 360

    tan2x+1=0
    This is what i did:
    tan2x+1=0
    tan2x= -1

    the places where tan = -1 between 0 and 360 are
    135, 315, 495, and 675 (divided these by 2 to get the actual angles)

    Actual angles are:
    67.5,157.5,202.5,337.5

    Those were my answers..
    the answer in the back of the book is 0 degrees
    I don't understand this??
    What am i missing
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  2. #2
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    Quote Originally Posted by tmas View Post
    Solve for x when x is between 0 and 360

    tan2x+1=0
    This is what i did:
    tan2x+1=0
    tan2x= -1

    the places where tan = -1 between 0 and 360 are
    135, 315, 495, and 675 (divided these by 2 to get the actual angles)

    Actual angles are:
    67.5,157.5,202.5,337.5

    Those were my answers..
    the answer in the back of the book is 0 degrees
    I don't understand this??
    What am i missing
    nothing, just a typo ...

    0 degrees is not a correct solution ... tan(0) + 1 does not equal 0

    0 < x < 360

    0 < 2x < 720

    tan(2x) = -1

    2x = 135 , 315, 495, 675

    x = 67.5, 157.5, 247.5, 337.5
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