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!

Finding the Derivative

  1. Feb 14, 2009 #1
    1. The problem statement, all variables and given/known data
    Find ds/dt for s=(t2)(1/7)


    2. Relevant equations
    I attempted to find the answer by using the chain rule...


    3. The attempt at a solution
    ds/dt = (1/7)*(t2)-(6/7)*(2t)
    ds/dt = (2/7)*t*(t2)-(6/7)

    I belive that would be the answer but the problem is that the answer key in the book tells me that ds/dt = (2/7)t-(5/7)

    I don't understand what they did to cancel out the t2 ang get the power to be -5/7
     
  2. jcsd
  3. Feb 14, 2009 #2
    Simplify 's' first before you take the derivative. Remember the properties of exponents.
     
  4. Feb 14, 2009 #3
    thanks i got it now that i said s=t(2/7)
     
  5. Feb 14, 2009 #4

    Mark44

    Staff: Mentor

    Your answer is correct, but it's not as simplified as it can be. Also, using the chain rule led to a lot of unnecessary work that could have been avoided by simplifying the expression first.

    (2/7)*t*(t2)-(6/7)
    =(2/7) *t* t-12/7
    =(2/7) *t7/7* t-12/7
    = (2/7) * t-5/7

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




Similar Discussions: Finding the Derivative
  1. Finding the derivative (Replies: 4)

  2. Find derivative (Replies: 1)

  3. Find the derivative. (Replies: 4)

  4. Find the Derivative (Replies: 12)

  5. Finding derivatives (Replies: 3)

Loading...