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Easy derivative

  1. Jul 5, 2009 #1
    1. The problem statement, all variables and given/known data

    Find the derivative:

    y=x^3-3(x^2+pi^2)

    2. Relevant equations



    3. The attempt at a solution

    y'=3x^2-6x-6pi

    But the book's answer emits -6pi

    What am I doing wrong?
     
  2. jcsd
  3. Jul 5, 2009 #2
    Pi is a constant. Derivative of Pi^2 with respect to x is zero.
     
  4. Jul 5, 2009 #3
    But it has power of two? Will that change anything?

    So derivative of pi^n n-all real numbers is zero?
     
  5. Jul 5, 2009 #4
    Pi=3.14
    Pi^2=9.87
    Pi^3=31 and so on
    As you can see that rasing a constant to real number power will result in a constant. Thus the derivative with respect to x will remain zero.

    Anyway I think you should recheck the question.
     
  6. Jul 5, 2009 #5
    Ok got it.

    What you mean recheck the question
     
  7. Jul 5, 2009 #6
    Well I don't think that y' is equal to -6pi for the given question. So recheck the question.
     
  8. Jul 5, 2009 #7
  9. Jul 5, 2009 #8
    Check this question. Neither answer is right.
     
  10. Jul 5, 2009 #9
    That was an attempt

    First one is not even the answer its the problem

    http://reactiondynamics.com/wp-content/uploads/2009/04/facepalm.gif
     
    Last edited by a moderator: Apr 24, 2017
  11. Jul 5, 2009 #10
    Oh I think I understand what's going on here. I think SELFMADE meant that "the book's answer 'omits' -6pi rather than 'emits'." Thus giving y'=3x^2-6x as the answer in the book, which is correct if I'm not mistaken.
     
  12. Jul 5, 2009 #11
    lol normal sunday morning typo, guys, sorry.
     
  13. Jul 5, 2009 #12

    HallsofIvy

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    Staff Emeritus
    Science Advisor

    I hate it when textbooks "emit" answers. You have to keep sweeping them up off the floor!:biggrin:
     
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