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Math Help - domain of functions 4

  1. #1
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    domain of functions 4

    how do you find the domain of the function f(x)=the square root of 3x-2
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    is up to his old tricks again! Jhevon's Avatar
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    Quote Originally Posted by bastropgarl View Post
    how do you find the domain of the function f(x)=the square root of 3x-2
    the domain of a function is the set of all input values (in this case, x-values) for which the functions is defined.

    \sqrt x is defined for all real numbers x such that x \ge 0.

    what do you think the domain off your function is?
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  3. #3
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    x is greater then or equal to -two over three
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  4. #4
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    Quote Originally Posted by bastropgarl View Post
    x is greater then or equal to -two over three
    Not -2/3 as f(-0.5) = \sqrt{-0.5}

    2/3 is the right magnitude but consider the sign
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  5. #5
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    sorry but im still not grasping this
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    is up to his old tricks again! Jhevon's Avatar
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    Quote Originally Posted by bastropgarl View Post
    sorry but im still not grasping this
    as e^(i*pi) said, all you needed to do was change the sign...

    The domain is all real x so that

    3x - 2 \ge 0

    \Rightarrow 3x \ge 2

    \Rightarrow x \ge \frac 23
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  7. #7
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    Quote Originally Posted by bastropgarl View Post
    sorry but im still not grasping this
    The equation to solve is the one posted by Jhevon immediately above.

    When I did f(-0.5) that was to prove that x \geq -\frac{2}{3} is not correct by picking a value of x that is greater than -2/3. The negative result shows it's incorrect
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