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Math Help - find the largest possible domain of this function

  1. #1
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    find the largest possible domain of this function

    find the largest possible domain of this function

    square root of pi/4-arcosx...everything is under the square root
    Last edited by mr fantastic; June 3rd 2011 at 03:43 AM. Reason: Copied title into main body of post.
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  2. #2
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    Quote Originally Posted by domenfrandolic View Post
    f:x


    square root of pi/4-arcosx...everything is under the square root
    Draw the graph of w = \frac{\pi}{4} - arccos(x). The implied domain will be the values of x for which w \geq 0.
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    the problem is i dont know how to do it
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    The square root is only defined for non-negative numbers so the domain is \frac{\pi}{4}- arccos(x)> 0 which is the same as saying that arccos(x)< \frac{\pi}{4}. One boundary of that will be where arccos(x)= \frac{\pi}{4} or x= cos(\pi/4). Remember that cosine is a decreasing function.
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    so the answer is cos(pi/4)?
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    Do you not understand what a "domain" is? The domain of a functions is a set of numbers, not a single number.
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    yeah i knew that but like which others are the answers?sorry about that but i am quit stuck with the given function
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    you should already know what the basic arccos function looks like ...



    perform the necessary transformations to obtain the graph of

    y = \frac{\pi}{4} - \arccos{x}

    then determine the interval where y \ge 0
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  9. #9
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    Quote Originally Posted by domenfrandolic View Post
    yeah i knew that but like which others are the answers?sorry about that but i am quit stuck with the given function
    Your problem is that you do not have a sufficient understanding of the pre-requisite mathematical knowledge assumed for this question. I suggest you go back to your class notes or textbook and review inverse trigonometric functions before making further attempts on this question.
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