Results 1 to 6 of 6

Math Help - the derivative of sec[f(x)] ?

  1. #1
    Junior Member
    Joined
    Aug 2008
    Posts
    60

    Question the derivative of sec[f(x)] ?

    would it be: sec[f'(x)]tan[f'(x)] f'(x) ?
    Follow Math Help Forum on Facebook and Google+

  2. #2
    MHF Contributor
    Joined
    Oct 2005
    From
    Earth
    Posts
    1,599
    Quote Originally Posted by sadieann View Post
    would it be: sec[f'(x)]tan[f'(x)] f'(x) ?
    Close.

    sec[f(x)]tan[f(x)]f'(x)
    Follow Math Help Forum on Facebook and Google+

  3. #3
    Junior Member
    Joined
    Aug 2008
    Posts
    60
    are you sure? that's not one of the choices on my homework
    Follow Math Help Forum on Facebook and Google+

  4. #4
    MHF Contributor
    Joined
    Oct 2005
    From
    Earth
    Posts
    1,599
    Quote Originally Posted by sadieann View Post
    are you sure? that's not one of the choices on my homework
    Yes. This is the basic idea of the chain rule. Let's say you have two functions, g(x) and f(x). d/dx g[f(x)] = g'[f(x)]*f'(x). What are the choices given?
    Follow Math Help Forum on Facebook and Google+

  5. #5
    Junior Member
    Joined
    Aug 2008
    Posts
    60
    The choices are:

    sec[f'(x)]tan[f'(x)]

    sec[f(x)]tan[f'(x)]f'(x)

    sec[f'(x)]tan[f(x)]f'(x)

    sec[f'(x)]tan[f'(x)]f'(x)

    tan[f(x)]f'(x)
    Follow Math Help Forum on Facebook and Google+

  6. #6
    MHF Contributor
    Joined
    Oct 2005
    From
    Earth
    Posts
    1,599
    I don't know what to tell you. I'm 99% sure I'm right and only doubting myself because of this weird situation. Problems are incorrectly written all the time. Do you follow my reasoning? This is a basic application of the chain rule.
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. contuous weak derivative $\Rightarrow$ classic derivative ?
    Posted in the Differential Geometry Forum
    Replies: 2
    Last Post: April 22nd 2011, 02:37 AM
  2. Replies: 0
    Last Post: January 24th 2011, 11:40 AM
  3. [SOLVED] Definition of Derivative/Alt. form of the derivative
    Posted in the Calculus Forum
    Replies: 2
    Last Post: September 23rd 2010, 06:33 AM
  4. Derivative Increasing ==> Derivative Continuous
    Posted in the Differential Geometry Forum
    Replies: 2
    Last Post: February 23rd 2010, 10:58 AM
  5. Replies: 2
    Last Post: November 6th 2009, 02:51 PM

Search Tags


/mathhelpforum @mathhelpforum