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Math Help - Can anyone help me finish this

  1. #1
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    Can anyone help me finish this

    Find the location of the indicated absolute extremum within the specified domain.
    Maximum of f(x) = x^2 - 4 ; [-1, 2]
    f'(x) = 2x
    f'(x) = 0
    2x = 0 => x = 0 ( what extremum is this?)
    f(x) = x^2 - 4
    f(-1)= 1 - 4 => f(-1) = - 3 (what extremum is this?)
    f(2)= 4 - 4 => f(2) = 0 (what extremum is this?)
    ( and also do i have it done right?)

    Thank you
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  2. #2
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    Quote Originally Posted by ArmiAldi View Post
    Find the location of the indicated absolute extremum within the specified domain.
    Maximum of f(x) = x^2 - 4 ; [-1, 2]
    f'(x) = 2x
    f'(x) = 0
    2x = 0 => x = 0 ( what extremum is this?)
    f(x) = x^2 - 4
    f(-1)= 1 - 4 => f(-1) = - 3 (what extremum is this?)
    f(2)= 4 - 4 => f(2) = 0 (what extremum is this?)
    ( and also do i have it done right?)

    Thank you
    Have you tried drawing a graph of f(x)?
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  3. #3
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    Quote Originally Posted by mr fantastic View Post
    Have you tried drawing a graph of f(x)?
    Thank You i try and for x = 2 and x = -2 graph is wierd , going trought same spot( 0 ). and what is extremum here 2?
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  4. #4
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    Quote Originally Posted by ArmiAldi View Post
    Thank You i try and for x = 2 and x = -2 graph is wierd , going trought same spot( 0 ). and what is extremum here 2?
    There are x-intercepts at x = x and x = -2. But you don't actually include x = -2. In fact you don't include x < -1 or x > 2 ....... You're only meant to draw it over [-1, 2] ....!

    How much experience do you have drawing graphs of parabolas?
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  5. #5
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    Quote Originally Posted by mr fantastic View Post
    There are x-intercepts at x = x and x = -2. But you don't actually include x = -2. In fact you don't include x < -1 or x > 2 ....... You're only meant to draw it over [-1, 2] ....!

    How much experience do you have drawing graphs of parabolas?
    That was very good question, when i was in high school ( 17 years ago ) math was my favorite study, then some things in my life changed , ( it is a long story). Last year Calculus with Applications
    ( Lial, Greenwell & Ritchey) and trying to do some of it. Very sorry because i took some of Your time with my questions, for 2 weeks how long I have been member i learn a lot ( also get banned because i put 3 times same thing, didnt know for that rule also sorry for that It was my faul)
    Anyway want to say Thank You to all of You.
    Let me answer Your question: I really can not remember a lot about graphs and parabolas. When i finish "my personal homework" probably will start learning graphs.
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