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anonymous

  • 5 years ago

What is the derivative of: 3x^4 - 2x^3 - 12x^2 + 18x

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  1. anonymous
    • 5 years ago
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    What'd you come up with? It's a pretty straight forward derivative to take.

  2. anonymous
    • 5 years ago
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    what i am wondering is if i should take an x out first. x(3x^3 - 2x^2 - 12x +18)

  3. anonymous
    • 5 years ago
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    Oh, no. Take the derivative term by term. It'll be much simplier.

  4. anonymous
    • 5 years ago
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    thanks

  5. anonymous
    • 5 years ago
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    In general I find it's easier to multiply out the products and take the derivative term by term unless it's a particularly hairy product with a lot of exponents, etc.

  6. anonymous
    • 5 years ago
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    ok, the whole problem is: Find all critical point of: (the orginal equation i entered) and use the second derivative test to classify each as a relative man and rel min or neither. it seems to be more difficult to get my critical points.

  7. anonymous
    • 5 years ago
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    \[f' = 12x^3 -6x^2 - 24x + 18\] \[f' = 0 \implies 2x^3 - x^2 - 4x + 3 = 0\]

  8. anonymous
    • 5 years ago
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    when you say taking the derivative, I am assuming you mean the derivative with respect to x? Therefore, the derivative would symply be: f'(x)=12x^3-6x^2-24x+18

  9. anonymous
    • 5 years ago
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    should have been relative max and rel min

  10. anonymous
    • 5 years ago
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    with having so many x's i am not sure how to find the critical points

  11. anonymous
    • 5 years ago
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    Yeah it's a tough one to factor.

  12. anonymous
    • 5 years ago
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    should i pull an x out before i get the derivative

  13. anonymous
    • 5 years ago
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    We can try..

  14. anonymous
    • 5 years ago
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    I'm not sure it'll make it better.

  15. anonymous
    • 5 years ago
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    i had done that already and it still has alot of x's

  16. anonymous
    • 5 years ago
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    It pretty much gives the same result. I was hoping it would be of a form that would better suggest how to factor.

  17. anonymous
    • 5 years ago
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    \(2x^3−x^2−4x+3=0\) \(x^2(2x-1) -(2x - 1) - (2x -1) -1\)

  18. anonymous
    • 5 years ago
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    Bleh. I need to practice dividing polynomials more apparently ;p

  19. anonymous
    • 5 years ago
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    WA claims it's \((x-1)^2(2x+3)\)

  20. anonymous
    • 5 years ago
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    thanks for your help. i will work on this again tomorrow

  21. anonymous
    • 5 years ago
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    one more quick question. should i go ahead and get the second derivative before i can get the critical points.

  22. anonymous
    • 5 years ago
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    i really dont think i will. i think i get the critical points from the first derivative and then i get the second derivative to test.

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