1. Limited time only! Sign up for a free 30min personal 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!

Partial derivative with chain rule: check work

  1. Mar 30, 2014 #1

    939

    User Avatar

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

    If possible, please check my work for any large errors.

    y = 10kl - √k - √l
    k = (t/5) + 5
    l = 5e^t/10

    Evaluate at t = 0 using chain rule.

    2. Relevant equations

    y = 10kl - √k - √l
    k = (t/5) + 5
    l = 5e^t/10

    3. The attempt at a solution

    = ∂y/∂k * dk/dt + ∂y/∂l * dl/dt
    = (10l - 0.5K^-0.5)(1/5) + (10k - 0.5l^-.05)((e^(x/10))/2)

    k(0) = 5
    l(0) = 5
    y(0) = ~9.95 + ~41.03 = ~51
     
  2. jcsd
  3. Mar 31, 2014 #2

    Mark44

    Staff: Mentor

    The above is close. The -0.5l^(-.05) term should be -0.5l^(-0.5). I don't know if that was a transcription error. Also, the exponential term would be clearer as (1/2)e(x/10).
    k(0) and l(0) are fine, but I didn't check your other numbers.

    One other thing. It's not good to start your first line with "=". For your problem, you should start with dy/dt = ...
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted



Similar Discussions: Partial derivative with chain rule: check work
Loading...