Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Homework Help: Differentiation of Trigonometric functions

  1. Dec 31, 2008 #1
    1. The problem statement, all variables and given/known data
    Let y = tan2(3x-2)
    Find dy/dx


    The solution is:
    2*tan(3x-2)*sec(3x-2)*3
    = 6*tan(3x-2)*sec2(3x-2)

    Why is it not:
    6*tan(3x-2)*sec(3x-2)

    I am thinking:
    y = (tan(3x-2))2
    take the power 2 down,multiply with the parentes multiply with the defferentiated parentes

    Edit: Happy new year
     
  2. jcsd
  3. Dec 31, 2008 #2

    tiny-tim

    User Avatar
    Science Advisor
    Homework Helper

    happy new year!

    Hi MaxManus! Happy new year! :smile:

    (what are parentes? :confused: do you mean "parenthesis"?)

    y = (thing)2,

    so y' = 2(thing)(thing') …

    in this case, the thing is a tan, and tan' = sec2 :wink:
     
  4. Dec 31, 2008 #3

    jgens

    User Avatar
    Gold Member

    What do you think d(tan(u))/dx is equivalent to?

    Edit: tiny-tim beat me to it.
     
  5. Dec 31, 2008 #4

    tiny-tim

    User Avatar
    Science Advisor
    Homework Helper

    happy new year!

    na na na na-na! :tongue:

    hic! :redface:

    :smile: happy new year! :smile:
     
  6. Dec 31, 2008 #5

    jgens

    User Avatar
    Gold Member

    Happy new year! :)
     
  7. Dec 31, 2008 #6
    Thanks tiny-tim and jgens.
    Yes, I ment parenthesis, but I could not spell it.
     
  8. Dec 31, 2008 #7

    HallsofIvy

    User Avatar
    Science Advisor

    Hitting the champagne a little early?
     
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook