Results 1 to 3 of 3

Math Help - Trig Function Derivs.

  1. #1
    Member
    Joined
    Nov 2007
    Posts
    112

    Trig Function Derivs.

    Find the derivative of the function below. Remember to use pi for π.
    g(x) = sin^2(10x) - pix

    alright just need to know how to do this problem.
    could some one show me in steps how to go about this one.
    thanks

    mathlete
    Follow Math Help Forum on Facebook and Google+

  2. #2
    GAMMA Mathematics
    colby2152's Avatar
    Joined
    Nov 2007
    From
    Alexandria, VA
    Posts
    1,172
    Awards
    1
    Quote Originally Posted by mathlete View Post
    Find the derivative of the function below. Remember to use pi for π.
    g(x) = sin^2(10x) - pix

    alright just need to know how to do this problem.
    could some one show me in steps how to go about this one.
    thanks

    mathlete
    g(x)=sin^2(10x) - \pi x

    g(x) = h(x) - \pi x

    To find the derivative, apply power rules, then chain and trig rules...

    g'(x) = h'(x) - \pi

    I am using the h function to show the chain rule.

    Chain rule says:

    h(x) = f(R(x))
    h'(x)=f'(R(x))*R'(x)

    We have:

    h(x) = sin^2(10x)
    h'(x) = 2sin(10x)*cos(10x)*10

    It's a double chain... now plug that back in!
    Follow Math Help Forum on Facebook and Google+

  3. #3
    Super Member Aryth's Avatar
    Joined
    Feb 2007
    From
    USA
    Posts
    651
    Thanks
    1
    Awards
    1
    Well, we know a few things:

    \frac{dy}{dx}[sin(x)] = cos(x)

    \frac{dy}{dx}[sin(10x)] = 10cos(10x)

    sin^2(10x) = sin(10x)sin(10x)

    g(x) = \underbrace{sin(10x)sin(10x)}_{\text{Use Product Rule}} - \underbrace{\pi x}_{\text{Use Power Rule}}

    Use the product rule for sin^2(10x) and using the above information, you should arrive at the derivative.
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Derivs heeelp
    Posted in the Calculus Forum
    Replies: 3
    Last Post: December 14th 2008, 07:36 PM
  2. More Inverse Derivs.
    Posted in the Calculus Forum
    Replies: 1
    Last Post: March 5th 2008, 11:15 AM
  3. trig derivs.
    Posted in the Calculus Forum
    Replies: 3
    Last Post: March 1st 2008, 05:06 AM
  4. inverse derivs...
    Posted in the Calculus Forum
    Replies: 3
    Last Post: October 5th 2007, 02:06 PM
  5. more derivs...
    Posted in the Calculus Forum
    Replies: 3
    Last Post: October 5th 2007, 01:34 AM

Search Tags


/mathhelpforum @mathhelpforum