Results 1 to 2 of 2

Math Help - Sine Curve Simultaneous equation help

  1. #1
    Newbie
    Joined
    May 2009
    Posts
    2

    Sine Curve Simultaneous equation help

    Hello everyone, this is my first post, be kind =).

    I have three sin curves, for 'biorhytms' (those lame scenarios they gives us for math assignments) each with a different period the equations are as follows;

    y=sin(2pi/33*x)
    y=sin(2pi/23*x)
    y=sin(2pi/28*x)

    where x is the number of days after birth. What I'm trying to find is the day in which all three curves equal zero, after x=0 of coruse. I get down to a whole number integar of the period on two for each one. And realised it must be a common multiple of all three, but how best do you show this? Thank you! Any help is much appreciated!
    Follow Math Help Forum on Facebook and Google+

  2. #2
    -1
    e^(i*pi)'s Avatar
    Joined
    Feb 2009
    From
    West Midlands, England
    Posts
    3,053
    Thanks
    1
    Quote Originally Posted by zooloo45 View Post
    Hello everyone, this is my first post, be kind =).

    I have three sin curves, for 'biorhytms' (those lame scenarios they gives us for math assignments) each with a different period the equations are as follows;

    y=sin(2pi/33*x)
    y=sin(2pi/23*x)
    y=sin(2pi/28*x)

    where x is the number of days after birth. What I'm trying to find is the day in which all three curves equal zero, after x=0 of coruse. I get down to a whole number integar of the period on two for each one. And realised it must be a common multiple of all three, but how best do you show this? Thank you! Any help is much appreciated!
    sin(k\pi) = 0 when k is an integer. In your case this would be when

    2x/33, 2x/23 and 2x/28 are all equal to an integer and therefore the LCD needs to be found.

    I find their LCD to be 21252 and so x = 10626
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Finding a cosine curve from a sine curve?
    Posted in the Trigonometry Forum
    Replies: 1
    Last Post: November 29th 2009, 03:40 AM
  2. Replies: 1
    Last Post: September 27th 2009, 05:16 PM
  3. Finding the period of a trigonmetic sine curve
    Posted in the Trigonometry Forum
    Replies: 5
    Last Post: September 25th 2009, 03:27 PM
  4. Topologist's sine curve is not path connected
    Posted in the Calculus Forum
    Replies: 1
    Last Post: February 12th 2009, 04:08 PM
  5. Replies: 8
    Last Post: October 8th 2007, 04:29 PM

Search Tags


/mathhelpforum @mathhelpforum