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Math Help - Solve trig. equations

  1. #1
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    Solve trig. equations

    Hi:
    Solve 6cosēθ-8sinx-3=0 , in the range 0 to 2∏

    I can't use Latex yet so I have uploaded a scanned attempt.
    My solutions are at:
    x=0.31
    x=2.83

    Am I close or in another game altogether?
    Attached Thumbnails Attached Thumbnails Solve trig. equations-solving-trig026.jpg  
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  2. #2
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    e^(i*pi)'s Avatar
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    Quote Originally Posted by stealthmaths View Post
    Hi:
    Solve 6cosēθ-8sinx-3=0 , in the range 0 to 2∏

    I can't use Latex yet so I have uploaded a scanned attempt.
    My solutions are at:
    x=0.31
    x=2.83

    Am I close or in another game altogether?
    Looks fine to me
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  3. #3
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    Quote Originally Posted by stealthmaths View Post
    Hi:
    Solve 6cosēθ-8sinx-3=0 , in the range 0 to 2∏

    I can't use Latex yet so I have uploaded a scanned attempt.
    My solutions are at:
    x=0.31
    x=2.83

    Am I close or in another game altogether?
    Hi stealthmaths,

    You've solved for Sinx or Sin\theta

    x=\theta=Sin^{-1}(0.31),\ \pi-Sin^{-1}(0.31)
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  4. #4
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    e^(i*pi)'s Avatar
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    Quote Originally Posted by Archie Meade View Post
    Hi stealthmaths,

    You've solved for Sinx or Sin\theta

    x=\theta=Sin^{-1}(0.31),\ \pi-Sin^{-1}(0.31)
    Ignore me, I'm a spoon >.<
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  5. #5
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    sinx=-4+√34/6
    sinx=0.3
    x=0.31

    So I plot on the sin graph where 0.31 is and draw along to find the second point and I get ∏-0.31
    giving 0.31 and 2.83

    What am I missing?
    I'm being a spoon?
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  6. #6
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    Looks fine,
    just checking that you took the inverse sine,
    you most likely did,
    answers are coincidental to 1 decimal place.
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  7. #7
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    yes. Great!
    Thank you both.
    I doubt your a spoon e^(i*pi)
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