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Math Help - Trigometric problem!

  1. #1
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    Trigometric problem!

    Hi, wondering if somebody could help me with this question,


    Use trigometric and hyperbolic identities to solve trigonometric equations.

    given that -15 cos(power2)x + 7 sinx + 11 = 0

    Solve for x between 0deg and 360deg

    Any help appreciated, been stressing with this all day.

    Thanks.
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  2. #2
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    Re: Trigometric problem!

    Quote Originally Posted by imonlyhuman View Post
    Hi, wondering if somebody could help me with this question,
    Use trigometric and hyperbolic identities to solve trigonometric equations.

    given that -15 \cos^2x + 7 \sin x + 11 = 0

    Solve for x between 0deg and 360deg
    Write it as -15(1-\sin^2(x))+7\sin(x)+11=0

    Now you have 15y^2+7y-4=0
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  3. #3
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    Re: Trigometric problem!

    Thank you for your reply Plato,

    This is where i get confused.. what i do next after 15y^2 + 7y - 4=0.

    Thanks.
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  4. #4
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    Re: Trigometric problem!

    Quote Originally Posted by imonlyhuman View Post
    This is where i get confused.. what i do next after 15y^2 + 7y - 4=0.
    how about factoring the quadratic and using the zero product property?
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  5. #5
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    Re: Trigometric problem!

    Thank you.
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