Advertise on Bikeforums.net



User Tag List

Results 1 to 6 of 6
  1. #1
    Senior Member AchiLLe..s's Avatar
    Join Date
    Oct 2005
    Location
    Suwanee, Georgia
    My Bikes
    Cannondale Caad 9
    Posts
    308
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)

    Calculus math problem

    How do you do the following:

    Find y' (y prime)

    y=(tanx)^(1/x)

    I have no clue how to do this problem

  2. #2
    Senior Member riff's Avatar
    Join Date
    Jul 2008
    Location
    TO
    Posts
    432
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    I think they want you to find the derivative ( ' ), ie find dy/dx if y=......

  3. #3
    Crushing souls Hickeydog's Avatar
    Join Date
    Jun 2007
    Location
    Sagamore Hills, Ohio.
    My Bikes
    Trek 1500
    Posts
    1,591
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Take the natural log of both sides (ln). Then you can take the (1/x) down to the front of the ln(tanx). Then take the dirivative of both sides.
    Quote Originally Posted by Wordbiker View Post

    What's frightening is how coherent Hickey was in posting that.

  4. #4
    Senior Member mojopt's Avatar
    Join Date
    Feb 2009
    Location
    SW Indiana
    Posts
    166
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    I found y'. It is in the second line of your post...

  5. #5
    Genius FlatMaster's Avatar
    Join Date
    Jan 2008
    Location
    Auburn, AL
    My Bikes
    Specilized Sirrus
    Posts
    324
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by Hickeydog View Post
    Take the natural log of both sides (ln). Then you can take the (1/x) down to the front of the ln(tanx). Then take the dirivative of both sides.
    When you do this and solve for yprime, you sill may have a y somewhere in your equation. You simply substitute your origional equation for y so you have a function of x only.
    Ride or Die

  6. #6
    T-Shirt Guy ehidle's Avatar
    Join Date
    Jul 2008
    Location
    Lansdale, PA
    My Bikes
    2005 Fuji Team Issue, 2007 Fuji SL-1
    Posts
    464
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Use the chain rule, then the quotient rule, then the chain rule again...

    Just a hint:

    tanx^(1/x) = exp(1/x ln tanx) and the exponential chain rule d exp(u)/du * du/dx where u = 1/x ln(tanx)
    Last edited by ehidle; 10-08-09 at 07:14 PM.
    Yellow + Blue Jerseys!

    Get your Cranky T-Shirt!
    Men's
    and Women's designs available

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •