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    I am really struggling with these types of questions where they ask you to work out what the maximum value of a trig function is and at what x-value it occurs etc.

    Would anyone be able to explain the theory behind this so I can understand these ques and work them out properly?

    Eg:

    Sin3X= 3sinx - 4sin^3x

    Determine the greatest posible value of:

    9 sin(10/3a) - 12 sin^3(10/3a)

    Apologies as i dont know how to use latex.
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    (Original post by major-major-major)
    I am really struggling with these types of questions where they ask you to work out what the maximum value of a trig function is and at what x-value it occurs etc.

    Would anyone be able to explain the theory behind this so I can understand these ques and work them out properly?

    Eg:

    Sin3X= 3sinx - 4sin^3x

    Determine the greatest posible value of:

    9 sin(10/3a) - 12 sin^3(10/3a)

    Apologies as i dont know how to use latex.
    If you mean the R\sin(x- \theta) and R\cos(x- \theta)

    Then the maximum value or minimum value is just 1 x R of the function. It is derived from the original \sin \theta and \cos \theta graphs

    EDIT: actually I've misread! For your example, it would be X = 10/3, so hence you want the maximum value of 3\sin(10/a^-1)

    I would think the answer is 3 :erm:
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    (Original post by .:excel4100%:.)
    If you mean the R\sin(x- \theta) and R\cos(x- \theta)

    Then the maximum value or minimum value is just 1 x R of the function. It is derived from the original \sin \theta and \cos \theta graphs

    So then how would you solve the equation above?
    :o:
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    you first draw a sin/cos graph, and see where the first max/min occur....in a sin graph your first max occurs at 90degrees


    so you do: x-Theta=90
    x= 90+Theta for you max etc
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    The answer to the above question is 9. I have no idea how to do these questions. !!!!!!!!!!!!!!!!!!!!!
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    (Original post by major-major-major)
    The answer to the above question is 9. I have no idea how to do these questions. !!!!!!!!!!!!!!!!!!!!!
    The answer would be 3. This is when sine of the angle is -1.

    -9 - (-12) = 3.

    When sine of the angle is 1, you get: 9 - 12 = -3

    When sine of the angle is 0, you get: 0 - 0 = 0
 
 
 
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