Results 1 to 4 of 4

Math Help - Show that the function...

  1. #1
    Member
    Joined
    Apr 2009
    Posts
    136
    Awards
    1

    Show that the function...

    Show that the function y=x(1-x)⁵ has a horizontal tangent at point P with a x coordinate 3/8. Show that the y coordinate of P is 3 x 5⁵ /8⁸.


    Sorry guys I have absolutely no idea. Was thinking along the lines of the product rule, but not sure. Help with working out appreciated.


    Cheers
    Follow Math Help Forum on Facebook and Google+

  2. #2
    Senior Member
    Joined
    Jan 2010
    Posts
    354
    The product rule is right. What are you getting when you try to apply the product rule?
    Follow Math Help Forum on Facebook and Google+

  3. #3
    Member
    Joined
    Apr 2009
    Posts
    136
    Awards
    1
    y=x(1-x)⁵

    y=3x(1-x)⁵ +15x⁴(1-x)⁴ ???
    Follow Math Help Forum on Facebook and Google+

  4. #4
    Member
    Joined
    Feb 2010
    Posts
    148
    Thanks
    2
    Quote Originally Posted by Joel View Post
    y=x(1-x)⁵

    y=3x(1-x)⁵ +15x⁴(1-x)⁴ ???
    y=x^3(1-x)^5

    Let f(x)=x^3

    Then f'(x)=3x^2

    Let g(x)=(1-x)^5

    Then g'(x)=5(1-x)^4(-1)

    y=f(x)g(x)

    y\,'=f(x)g'(x)+g(x)f'(x)

    So what would you get for y\,'?

    To show that y has a horizontal tangent line at x=\frac{3}{8}, you need to show that y\,'=0 when x=\frac{3}{8}
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Replies: 3
    Last Post: November 29th 2011, 02:08 PM
  2. [SOLVED] Show that the function is a decreasing function
    Posted in the Calculus Forum
    Replies: 8
    Last Post: June 2nd 2011, 05:55 AM
  3. Show that function is bounded
    Posted in the Differential Geometry Forum
    Replies: 6
    Last Post: April 10th 2011, 12:13 PM
  4. show that the function is not 1-1
    Posted in the Differential Geometry Forum
    Replies: 6
    Last Post: April 25th 2010, 02:02 AM
  5. show the function is an entire function
    Posted in the Calculus Forum
    Replies: 1
    Last Post: March 24th 2010, 10:46 PM

Search Tags


/mathhelpforum @mathhelpforum