Results 1 to 4 of 4

Math Help - Circumference and Area of circle

  1. #1
    Newbie
    Joined
    Mar 2011
    Posts
    7

    Circumference and Area of circle

    Why is it that the circumference of the circle is given by 2rPi which is the derivative of r^2Pi by r, which gives the area of it. Same if we transfer it to cartesian coordinates, y= Sqrt(r^2-x^2) the arc length is given by r(arcsin(x/r)) which is the derivative of r(arcsin(x/r) + r/2(Sqrt(r^2-x^2))) which on the other hand gives the area of the quarter circle with radius r. The same applies to the sphere. Can this be extended to the n-dimensional circle? (sphere: V=4/3Pir^3 SA= 4Pir^2)

    its just something interesting i found today and was wondering abt the explanation behind this.
    Follow Math Help Forum on Facebook and Google+

  2. #2
    Newbie
    Joined
    Mar 2011
    Posts
    7

    Re: Circumference and Area of circle

    anyone?
    Follow Math Help Forum on Facebook and Google+

  3. #3
    MHF Contributor
    Joined
    Oct 2009
    Posts
    5,561
    Thanks
    785

    Re: Circumference and Area of circle

    Googling for "circumference is derivative of area" gives a lot of results.
    Follow Math Help Forum on Facebook and Google+

  4. #4
    Newbie
    Joined
    Mar 2011
    Posts
    7

    Re: Circumference and Area of circle

    right. i couldve done that too, but i was looking for a more formal reasoning from someone who knows what hes talking about not yahoo answers with 13 year old kids so i came here.
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Area and Circumference of the circle relation
    Posted in the Calculus Forum
    Replies: 2
    Last Post: October 18th 2011, 04:16 PM
  2. Replies: 4
    Last Post: February 10th 2011, 09:14 AM
  3. pdf of area and circumference of a circle
    Posted in the Advanced Statistics Forum
    Replies: 6
    Last Post: May 10th 2010, 10:56 PM
  4. Circle area and circumference
    Posted in the Geometry Forum
    Replies: 2
    Last Post: August 30th 2009, 04:19 PM
  5. Replies: 3
    Last Post: April 3rd 2009, 08:15 PM

Search Tags


/mathhelpforum @mathhelpforum