Results 1 to 2 of 2

Math Help - quick question

  1. #1
    Senior Member
    Joined
    Aug 2009
    Posts
    349

    quick question

    what is the derivative of cos squared of x? is it -2 sin x? thx in advance
    Follow Math Help Forum on Facebook and Google+

  2. #2
    -1
    e^(i*pi)'s Avatar
    Joined
    Feb 2009
    From
    West Midlands, England
    Posts
    3,053
    Thanks
    1
    Quote Originally Posted by slapmaxwell1 View Post
    what is the derivative of cos squared of x? is it -2 sin x? thx in advance
    No it isn't - recall the chain rule

    \frac{d}{dx} \, cos^2(x) = -2cos(x)sin(x) = -sin(2x)


    ==============================

    \frac{d}{dx} \, cos(x^2) = -2xsin(x^2)
    Last edited by e^(i*pi); January 16th 2010 at 09:20 AM. Reason: added in d/dx cos(x^2)
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. quick question...
    Posted in the Calculus Forum
    Replies: 8
    Last Post: January 23rd 2011, 06:20 AM
  2. One more quick question
    Posted in the Algebra Forum
    Replies: 1
    Last Post: November 11th 2010, 11:06 PM
  3. Quick question: what is sup and what is inf of this set?
    Posted in the Differential Geometry Forum
    Replies: 1
    Last Post: October 15th 2009, 01:29 PM
  4. Quick question...
    Posted in the Advanced Algebra Forum
    Replies: 2
    Last Post: September 2nd 2008, 11:53 AM
  5. Quick's quick question
    Posted in the Number Theory Forum
    Replies: 22
    Last Post: July 9th 2006, 04:38 PM

Search Tags


/mathhelpforum @mathhelpforum