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Math Help - Solving Trig Equations

  1. #1
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    Solving Trig Equations

    Ok, I have to take an accuplacer, I was doing a practice test online to prepare. I was given the equation:

    \sin(2\theta)+3=4

    I need to find \theta

    \sin(2\theta)=1

    When the sine of an angle is equal to one on [0,2\pi] then the angle must be equal to \frac{\pi}{2} right? So I have:

    2\theta=\frac{\pi}{2}

    \theta=\pi

    The practice test I as doing is mulitple choice. Of course \pi was actually the wrong answer . Where am I going wrong here?
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  2. #2
    MHF Contributor alexmahone's Avatar
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    Quote Originally Posted by adkinsjr View Post
    Ok, I have to take an accuplacer, I was doing a practice test online to prepare. I was given the equation:

    \sin(2\theta)+3=4

    I need to find \theta

    \sin(2\theta)=1

    When the sine of an angle is equal to one on [0,2\pi] then the angle must be equal to \frac{\pi}{2} right? So I have:

    2\theta=\frac{\pi}{2}

    \theta=\frac{\pi}{4}
    Fixed the last statement.
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  3. #3
    Senior Member pacman's Avatar
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    You screwed the last line of your solution,

    it should be pi/4 not pi
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  4. #4
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    lol, ok

    thanks.
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