Results 1 to 6 of 6

Math Help - Estimation

  1. #1
    Junior Member
    Joined
    Sep 2008
    Posts
    30

    Estimation

    Hi,

    z= cos(x) sin(x) , x <= |0.1|

    I want to estimate z

    I know that |z| <= |1| , but is there is a more accurate estimation ?


    thx
    Last edited by Musab; May 28th 2009 at 03:19 AM.
    Follow Math Help Forum on Facebook and Google+

  2. #2
    Senior Member
    Joined
    Nov 2008
    Posts
    461
    Hello.

    Quote Originally Posted by Musab View Post
    Hi,

    z= cos(x) sin(x) , x <= |0.1|

    I want to estimate z

    I know that |z| <= 1 , but is there is a more accurate estimation ?

    thx
    What exactly are you asking for?

    z is continious on x <= |0.1|, you can say something about slope and it has the sin-symmetry. And you know z(0) = 0; there are no zeros except for x=0 on your interval...

    Yours
    Rapha
    Follow Math Help Forum on Facebook and Google+

  3. #3
    MHF Contributor
    Opalg's Avatar
    Joined
    Aug 2007
    From
    Leeds, UK
    Posts
    4,041
    Thanks
    7
    Quote Originally Posted by Musab View Post
    Hi,

    z= cos(x) sin(x) , x <= |0.1|

    I want to estimate z

    I know that |z| <= 1 , but is there is a more accurate estimation ?
    To a first approximation, z = x. If you want something more accurate, the next approximations are z = x-\tfrac23x^3 and z = x-\tfrac23x^3 + \tfrac2{15}x^5.
    Follow Math Help Forum on Facebook and Google+

  4. #4
    Junior Member
    Joined
    Sep 2008
    Posts
    30
    I think I haven't explained what I want properly.


    |z| <= | n | where n is a number

    I want to know the smallest possible value of |n| , so that the accuracy of the approximation rises.

    thx
    Follow Math Help Forum on Facebook and Google+

  5. #5
    Junior Member
    Joined
    Sep 2008
    Posts
    30
    is this right :

    |z|<= |cos(0) sin(0.1) | ??
    Follow Math Help Forum on Facebook and Google+

  6. #6
    MHF Contributor Amer's Avatar
    Joined
    May 2009
    From
    Jordan
    Posts
    1,093
    z dose not equal 1 it is impossible cuz

    sinx cosx=sin2x/2 and the largest value of this is 1/2
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Estimation
    Posted in the Advanced Statistics Forum
    Replies: 2
    Last Post: September 21st 2010, 05:55 AM
  2. Estimation
    Posted in the Advanced Statistics Forum
    Replies: 1
    Last Post: April 12th 2010, 01:42 AM
  3. MLE estimation
    Posted in the Advanced Statistics Forum
    Replies: 4
    Last Post: March 18th 2010, 05:38 PM
  4. estimation
    Posted in the Advanced Statistics Forum
    Replies: 1
    Last Post: May 28th 2009, 11:50 PM
  5. Estimation
    Posted in the Statistics Forum
    Replies: 0
    Last Post: April 22nd 2009, 03:19 AM

Search Tags


/mathhelpforum @mathhelpforum