1. Not finding help here? Sign up for a free 30min tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

First & Second derivative of a function

  1. Feb 7, 2010 #1
    1. The problem statement, all variables and given/known data
    The function Sh(t) = 30[cos(16.04*)]t models the horizantal position of a pellet with respect to time.

    Find the first & second derivatives of Sh(t).



    2. Relevant equations


    3. The attempt at a solution I attached a word document because I lack the ability to put together a correctly formatted latex doc in my post. I apologize for the inconvenience. Thank you in advance.

    Joe


    1. The problem statement, all variables and given/known data



    2. Relevant equations



    3. The attempt at a solution
    1. The problem statement, all variables and given/known data



    2. Relevant equations



    3. The attempt at a solution
    1. The problem statement, all variables and given/known data



    2. Relevant equations



    3. The attempt at a solution
     

    Attached Files:

  2. jcsd
  3. Feb 7, 2010 #2
    Sh(t) = 30[cos(16.04*)]t
    1st derivative 30cos(16.04)
    2nd 0
    If the t is in the cos function, then
    1st 16.04*30*(-sin16.04t)
    2nd 16.04^2*30*(-cos16.04t)
     
  4. Feb 7, 2010 #3

    vela

    User Avatar
    Staff Emeritus
    Science Advisor
    Homework Helper
    Education Advisor

    The first term in the numerator of your limit should be [itex]30(\cos 16.04^\circ)(t+\Delta t)[/itex], so [itex]\Delta t[/itex] gets multiplied by the constant.
     
  5. Feb 7, 2010 #4
    I didn't download the paper. I just responded to what the derivatices would be based on what is giving. You need to do the limit definition to obtain the derivatives?
     
  6. Feb 8, 2010 #5
    So for my first derivative I get to an answer of delta t/delta t, which I'm sure isn't correct. Are there some rules for differentiating when trig functions are involved that differs from a function say f(x)=x^3 ? Also I posted this question incorrectly as I was going off memory the first time. In the real problem there is no limit written next to the function, does this change things at all? I figured that equation without a limit is just the slope of a secant line. Thanks in advance.

    Joe
     
    Last edited: Feb 8, 2010
  7. Feb 8, 2010 #6
    Re: First & Second derivative of a function [Solved]

    I figured it out. I was missing some rules for derivatives such as f(x)= a constant * a variable, then f'(x) =the constant. Another one was f'(x) of a constant =0. This is of course what Dustin was trying to tell me, I just couldn't put it together from that context. Thanks for your help gentlemen.

    Joe
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?



Similar Discussions: First & Second derivative of a function
Loading...