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    I have cos \theta = \frac{-4}{9} and want to find an exact value for  sin \theta. My calculator will not give this to me as an exact value.

    If this was cos \theta = \frac{4}{9} it would not be a problem as i can use the triangle method. But not sure how to go about the negative sign.

    Please help?
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    \sin^2 \theta = 1- \cos^2 \theta
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    (Original post by Random999)
    I have cos \theta = \frac{-4}{9} and want to find an exact value for  sin \theta. My calculator will not give this to me as an exact value.

    If this was cos \theta = \frac{4}{9} it would not be a problem as i can use the triangle method. But not sure how to go about the negative sign.

    Please help?
    sin(x)=cos(x-0.5pi)
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    (Original post by Mr M)
    \sin^2 \theta = 1- \cos^2 \theta
    Thanks. Knew it had to be something simple.
 
 
 
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