Results 1 to 3 of 3

Math Help - Help? Parametric and circle questions

  1. #1
    Junior Member
    Joined
    Sep 2008
    Posts
    61

    Help? Parametric and circle questions

    1. Find two different parametric descriptions for he circle of radiu 4 centered at (-3, 2).







    2. The radius of the circumscribed circle of the triangle ABC is 15 cm. Given that B is a 49-degree angle, find the length of side AC.
    Follow Math Help Forum on Facebook and Google+

  2. #2
    MHF Contributor
    Joined
    Apr 2008
    Posts
    1,092
    1. A circle of radius 4 centered at (-3, 2) has the equation (x + 3)^2 + (y - 2)^2 = 16. However, you can use trigonometric functions to establish a circular path with center (h, k) and radius r:

    x = h + r \sin t
    y = k + r \cos t

    or

    x = h + r \cos t
    y = k + r \sin t.

    The first represents a clockwise path, and the second represents a counterclockwise path.
    Follow Math Help Forum on Facebook and Google+

  3. #3
    Super Member

    Joined
    May 2006
    From
    Lexington, MA (USA)
    Posts
    11,904
    Thanks
    765
    Hello, pyrosilver!

    2. The radius of the circumscribed circle of the \Delta ABC is 15 cm.
    Given that \angle B = 49^o, find the length of side AC.
    Code:
                    A
                  * o *
              *    /*\    *
            *     / * \     *
           *     /  *  \     *
                / 15*   \
          *    /    *    \    *
          *   /    Po 98 \   *
          *  /         *   \  *
            / 49      15 * \
         B o - - - - - - - - o C
            *               *
              *           *
                  * * *

    The center of the circle is P.

    Draw radii PA = PC = 15

    Since inscribed angle ABC = 49^o, then central angle APC = 98^o

    Use the Law of Cosines on \Delta APC.

    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Parametric equations, circle, center, radius
    Posted in the Calculus Forum
    Replies: 4
    Last Post: February 9th 2011, 05:42 AM
  2. parametric equations of great circle on sphere
    Posted in the Calculus Forum
    Replies: 2
    Last Post: January 2nd 2011, 09:29 AM
  3. parametric equations(movement around a circle)
    Posted in the Calculus Forum
    Replies: 6
    Last Post: August 27th 2009, 01:17 PM
  4. Parametric equation for the circle..
    Posted in the Geometry Forum
    Replies: 1
    Last Post: December 6th 2008, 12:40 AM
  5. parametric circle
    Posted in the Pre-Calculus Forum
    Replies: 2
    Last Post: October 19th 2007, 04:49 AM

Search Tags


/mathhelpforum @mathhelpforum