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Math Help - Question about functions and a identity Question

  1. #1
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    Question about functions and a identity Question

    I have two quick questions about basic trig.My first question is asking to find period, amplitude, and phase shift of a function written as

    f(x) = -cos(pi(x - 0.1))

    Can i write the function as

    f(x) = -cos(pi x - 0.1)?

    Also I was asked to find the values of x between [0, 2pi] of the following equation

    2sin^2 = 1

    When i solve this equation I get

    sinx = 1/ root 2

    There is no special angle or this solution so would I use a decimal approximation?

    Thanks for any help
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  2. #2
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    Quote Originally Posted by fishguts View Post
    I have two quick questions about basic trig.My first question is asking to find period, amplitude, and phase shift of a function written as

    f(x) = -cos(pi(x - 0.1))

    Can i write the function as

    f(x) = -cos(pi x - 0.1)? Mr F says: No. {\color{red}f(x) = - \cos (\pi x - 0.1 \pi)}.

    Also I was asked to find the values of x between [0, 2pi] of the following equation

    2sin^2 = 1

    When i solve this equation I get

    sinx = 1/ root 2 Mr F says: {\color{red}\sin x = \pm \frac{1}{\sqrt{2}} = \pm \frac{\sqrt{2}}{2}}.

    There is no special angle Mr F says: Yes there is.

    or this solution so would I use a decimal approximation? Mr F says: No. See above.

    Thanks for any help
    ..
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  3. #3
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    Quote Originally Posted by mr fantastic View Post
    ..

    Thanks man for the first one I forgot to rationalize the denominator that why I was not getting that one, and the second problem I was not too sure. And also sorry about the syntax
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