Results 1 to 7 of 7

Math Help - parametric equations(movement around a circle)

  1. #1
    Newbie
    Joined
    Mar 2009
    Posts
    16

    parametric equations(movement around a circle)

    So here's the question: Find the parametric equations of a circle with radius 4 and with a center of (3,9) moving counterclockwise around the circle once.

    I worked through it and got:

    x= 4cosTheta + 3

    y= 4sinTheta + 9

    0<theta<2pi

    Although I have no idea about the movement around the circle part.
    Follow Math Help Forum on Facebook and Google+

  2. #2
    Member eXist's Avatar
    Joined
    Aug 2009
    Posts
    157
    Well as \theta goes from 0 \Rightarrow 2\pi which direction does it travel normally?

    (Although your answer I believe is correct as it stands, think about this question so you'll know next time)
    Follow Math Help Forum on Facebook and Google+

  3. #3
    Newbie
    Joined
    Mar 2009
    Posts
    16
    I'm pretty sure its Counter clockwise, but if the problem said, for example, it was going clockwise, what would that mean?
    Follow Math Help Forum on Facebook and Google+

  4. #4
    Member eXist's Avatar
    Joined
    Aug 2009
    Posts
    157
    You are correct, \theta from 0 \Rightarrow 2\pi the rotation is counter-clockwise.

    In order to go clockwise, you would state something like:

    \theta from 2\pi \Rightarrow 0
    Follow Math Help Forum on Facebook and Google+

  5. #5
    Newbie
    Joined
    Mar 2009
    Posts
    16
    Quote Originally Posted by eXist View Post
    You are correct, from 0 \Rightarrow 2\pi the rotation is counter-clockwise.

    In order to go clockwise, you would state something like:

    \theta from 2\pi \Rightarrow 0
    Would changing the direction change my answer, because I've seen other problems like that and wasn't sure what to do?
    Follow Math Help Forum on Facebook and Google+

  6. #6
    Member eXist's Avatar
    Joined
    Aug 2009
    Posts
    157
    Quote Originally Posted by rioneye View Post
    Would changing the direction change my answer, because I've seen other problems like that and wasn't sure what to do?
    Yes, changing your answer would, but you already have it going counter-clockwise. So your answer is correct as it is. I was merely showing you how to reverse the direction if you needed to.
    Follow Math Help Forum on Facebook and Google+

  7. #7
    Newbie
    Joined
    Mar 2009
    Posts
    16
    Quote Originally Posted by eXist View Post
    Yes, changing your answer would, but you already have it going counter-clockwise. So your answer is correct as it is. I was merely showing you how to reverse the direction if you needed to.
    ok thank you
    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 equation for the circle..
    Posted in the Geometry Forum
    Replies: 1
    Last Post: December 6th 2008, 12:40 AM
  4. Help? Parametric and circle questions
    Posted in the Pre-Calculus Forum
    Replies: 2
    Last Post: October 4th 2008, 02:43 PM
  5. parametric circle
    Posted in the Pre-Calculus Forum
    Replies: 2
    Last Post: October 19th 2007, 04:49 AM

Search Tags


/mathhelpforum @mathhelpforum