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Math Help - Finding Reference Angle

  1. #1
    Senior Member vaironxxrd's Avatar
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    Finding Reference Angle

    Hello again and again Everyone,

    I'm having trouble finding a reference angle for the following angle.

    \theta = -1.8

    The book provides me with the answer which is \theta' \approx 1.342
    But I cannot reach it, through my procedures.

    I know the following is WRONG. But I'm trying to layout my method, to know where am I messing up.
    I'm converting theta to be degrees, since it is easier for me.
    -1.8 * 180 = -324
    Angle coterminal to -324 = 36
    Reference angle = 90 - 36
    ^- This is definitely wrong but I can't think of any other methods.
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    Forum Admin topsquark's Avatar
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    Re: Finding Reference Angle

    Quote Originally Posted by vaironxxrd View Post
    Hello again and again Everyone,

    I'm having trouble finding a reference angle for the following angle.

    \theta = -1.8

    The book provides me with the answer which is \theta' \approx 1.342
    But I cannot reach it, through my procedures.

    I know the following is WRONG. But I'm trying to layout my method, to know where am I messing up.
    I'm converting theta to be degrees, since it is easier for me.
    -1.8 * 180 = -324
    Angle coterminal to -324 = 36
    Reference angle = 90 - 36
    ^- This is definitely wrong but I can't think of any other methods.
    Your angle is in quadrant IV so the reference angle of +324 would be 360 - 324 = 36.

    Also, did you remember to convert back to radians?

    -Dan
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    Re: Finding Reference Angle

    Quote Originally Posted by vaironxxrd View Post
    Hello again and again Everyone,
    I'm having trouble finding a reference angle for the following angle.
    \theta = -1.8
    The book provides me with the answer which is \theta' \approx 1.342
    Please forget about ever using degrees.
    Take a look at this webpage.

    Because \frac{\pi}{2}<1.8<\pi the reference angle is \pi-1.8.
    Thanks from topsquark
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  4. #4
    Senior Member vaironxxrd's Avatar
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    Re: Finding Reference Angle

    Quote Originally Posted by Plato View Post
    Please forget about ever using degrees.
    Take a look at this webpage.

    Because \frac{\pi}{2}<1.8<\pi the reference angle is \pi-1.8.
    Really... Just forget about it ?
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