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haleyelizabeth2017

  • one year ago

For which interval(s) is f(x)=3x^3-16x+2 increasing or decreasing?

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  1. freckles
    • one year ago
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    You could find f'(x). Then find where f'>0 (this is where f is increasing) Then find where f'<0 (this is where f is decreasing)

  2. Koikkara
    • one year ago
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    |dw:1443816836547:dw| Graph comes like this.. lol and Hai...

  3. Koikkara
    • one year ago
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    @haleyelizabeth2017 Which means it's increasing...lol

  4. haleyelizabeth2017
    • one year ago
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    lol I have to find the intervals...

  5. freckles
    • one year ago
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    @haleyelizabeth2017 have you found the critical numbers yet?

  6. haleyelizabeth2017
    • one year ago
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    No, still working on it.

  7. haleyelizabeth2017
    • one year ago
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    Do I set f(x) to 0 and solve for x?

  8. freckles
    • one year ago
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    To find critical numbers you solve f'(x)=0 for x.

  9. freckles
    • one year ago
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    not f(x)=0

  10. haleyelizabeth2017
    • one year ago
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    f'(x)?

  11. freckles
    • one year ago
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    yes derivative of f

  12. freckles
    • one year ago
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    do you know any calculus?

  13. freckles
    • one year ago
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    or you suppose to graph it in your calculator and say where the function is increasing or decreasing?

  14. haleyelizabeth2017
    • one year ago
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    I do not know any calculus lol...

  15. freckles
    • one year ago
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    Well how do they expect you to answer this? Calculator right?

  16. haleyelizabeth2017
    • one year ago
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    I think so

  17. freckles
    • one year ago
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    |dw:1443817293708:dw| we need to find these numbers a and b

  18. freckles
    • one year ago
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    read the function from left to right

  19. freckles
    • one year ago
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    the function is rising on (-inf,a) then falling on (a,b) then rising again on (b,inf)

  20. freckles
    • one year ago
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    all you have to do now is find those numbers a and b also called the turning points of the function using your calculator

  21. freckles
    • one year ago
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    also let me put some numbers on my graph because I don't want you to think that is y=0... |dw:1443817470752:dw| it was just meant to be a rough picture anyways

  22. freckles
    • one year ago
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    those equations aren't even that important (talking about the x=0 and the y=2)

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