1. Not finding help here? Sign up for a free 30min tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Tangent Lines

  1. Mar 29, 2009 #1
    The problem statement, all variables and given/known data[/b]
    My book talks about find the two tangent lines at the point (0,2) for http://mathbin.net/equations/7402_0.png [Broken] and http://mathbin.net/equations/7402_1.png [Broken].[/URL] It says that t then is equal to pi/2 and -pi/2. I do not know how to they solved for this t. Any help?
     
    Last edited by a moderator: May 4, 2017
  2. jcsd
  3. Mar 29, 2009 #2

    CompuChip

    User Avatar
    Science Advisor
    Homework Helper

    You solve the simultaneous equation
    [tex]x = 0, y = 2[/tex]

    It's easiest starting with the latter:
    [tex]2 = y = 2 - \pi \cos t \implies 0 = - \pi \cos t \implies t = \pm \frac{\pi}{2}[/tex]
    and then all you have to do is plug them both into the equation for x and check that it gives zero (i.e. you have two values of t for which (0, 2) is on the curve).
     
  4. Mar 29, 2009 #3
    Why didn't we include [tex]\frac{ \pi }{2}+2n \pi[/tex]?

    Thank you!
     
  5. Mar 29, 2009 #4

    CompuChip

    User Avatar
    Science Advisor
    Homework Helper

    Because there are no such points at which the curve goes through (0, 2).
    You can plug it in:
    x(pi/2 + 2 pi) = ... ?
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook




Similar Discussions: Tangent Lines
  1. Tangent Line (Replies: 4)

  2. Tangent Line (Replies: 6)

  3. Tangent lines (Replies: 1)

  4. Tangent of a line (Replies: 14)

  5. Tangent line (Replies: 4)

Loading...