Results 1 to 2 of 2

Math Help - Finding the tangent line!

  1. #1
    Member
    Joined
    Nov 2007
    Posts
    112

    Finding the tangent line!

    Find the equation of the line tangent to the curve y = (sin(x))(cos(x))
    at the point (pi/4, 1/2).

    im usually good with finding tangent lines from this kinda stuff, but this one doesnt seem to work for me...any help

    thanks
    Follow Math Help Forum on Facebook and Google+

  2. #2
    Super Member
    earboth's Avatar
    Joined
    Jan 2006
    From
    Germany
    Posts
    5,807
    Thanks
    116
    Quote Originally Posted by mathlete View Post
    Find the equation of the line tangent to the curve y = (sin(x))(cos(x))
    at the point (pi/4, 1/2).

    ...
    Use product rule:

    f'(x)=\cos(x) \cdot \cos(x) + \sin(x) \cdot (-\sin(x)) = \cos^2(x)-\sin^2(x) =  \cos^2(x) -(1-\cos^2(x) = 2\cos^2(x) - 1

    Then f'(\frac{\pi}{4}) = 0 and therefore the equation of the tangent is y = \frac12
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Replies: 6
    Last Post: January 12th 2011, 02:38 PM
  2. Finding a tangent line
    Posted in the Calculus Forum
    Replies: 4
    Last Post: January 2nd 2011, 11:01 AM
  3. finding the tangent line
    Posted in the Calculus Forum
    Replies: 1
    Last Post: March 7th 2010, 11:07 PM
  4. Finding the tangent line
    Posted in the Calculus Forum
    Replies: 1
    Last Post: October 19th 2009, 11:27 AM
  5. Finding a tangent line
    Posted in the Pre-Calculus Forum
    Replies: 2
    Last Post: June 12th 2009, 05:14 PM

Search Tags


/mathhelpforum @mathhelpforum