Results 1 to 3 of 3

Math Help - Derivatives with Trig and Natural Logs

  1. #1
    Newbie
    Joined
    Aug 2011
    Posts
    22

    Derivatives with Trig and Natural Logs

    I missed the last couple of lectures because I've been sick, and haven't been able to copy the notes yet. I actually have a quiz on this stuff tomorrow, so if anyone knows of a website that could explain this stuff, then I'd be really grateful.

    1) Derivative of f(x)=sin(ln(x))
    I obviously don't know what to do...I Googled and found out that the derivative of ln x=1/x, so I tried doing the derivative of sin(1/x), but that didn't work, and I wasn't really sure how to do it.

    2) Derivative of (4 - ln(x)) / (2 + ln(x))
    Again, no clue how to do this, so any help is appreciated.

    Thanks in advance!
    Follow Math Help Forum on Facebook and Google+

  2. #2
    Senior Member
    Joined
    Nov 2010
    From
    Clarksville, ARk
    Posts
    398

    Re: Derivatives with Trig and Natural Logs

    Quote Originally Posted by xxStrikeback View Post
    I missed the last couple of lectures because I've been sick, and haven't been able to copy the notes yet. I actually have a quiz on this stuff tomorrow, so if anyone knows of a website that could explain this stuff, then I'd be really grateful.

    1) Derivative of f(x)=sin(ln(x))
    I obviously don't know what to do...I Googled and found out that the derivative of ln x=1/x, so I tried doing the derivative of sin(1/x), but that didn't work, and I wasn't really sure how to do it.
    For (1): Use the chain rule.

    sin(1/x) is not involved in this problem.

    2) Derivative of (4 - ln(x)) / (2 + ln(x))
    Use the quotient rule.
    Follow Math Help Forum on Facebook and Google+

  3. #3
    MHF Contributor
    skeeter's Avatar
    Joined
    Jun 2008
    From
    North Texas
    Posts
    11,621
    Thanks
    426

    Re: Derivatives with Trig and Natural Logs

    Quote Originally Posted by xxStrikeback View Post
    I missed the last couple of lectures because I've been sick, and haven't been able to copy the notes yet. I actually have a quiz on this stuff tomorrow, so if anyone knows of a website that could explain this stuff, then I'd be really grateful.

    1) Derivative of f(x)=sin(ln(x))
    I obviously don't know what to do...I Googled and found out that the derivative of ln x=1/x, so I tried doing the derivative of sin(1/x), but that didn't work, and I wasn't really sure how to do it.

    2) Derivative of (4 - ln(x)) / (2 + ln(x))
    Again, no clue how to do this, so any help is appreciated.

    Thanks in advance!
    1. chain rule ... \frac{d}{dx} \sin{u} = \cos{u} \cdot \frac{du}{dx} ... where u = \ln{x}

    2. quotient rule.
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Replies: 9
    Last Post: February 22nd 2011, 05:39 PM
  2. derivatives with natural logs
    Posted in the Calculus Forum
    Replies: 3
    Last Post: May 4th 2010, 01:02 PM
  3. derivatives using natural logs
    Posted in the Calculus Forum
    Replies: 3
    Last Post: September 30th 2009, 08:55 PM
  4. Replies: 6
    Last Post: March 18th 2009, 04:10 AM
  5. Derivatives of Natural Logs question
    Posted in the Calculus Forum
    Replies: 3
    Last Post: July 25th 2007, 03:13 PM

Search Tags


/mathhelpforum @mathhelpforum