Results 1 to 5 of 5

Math Help - Solving an equasion Implicitly, Hydraulics Question

  1. #1
    Newbie
    Joined
    Jan 2013
    From
    St. Johns
    Posts
    1

    Solving an equasion Implicitly, Hydraulics Question

    Ok, so I am trying to solve this equasion for y

    0.33392=(1/0.027)*(y+2*y^2)*((y+2*y^2)/(2.236+4.472*y))^(2/3)

    I should probably know how to do this myself (I've done a million and one math courses over the past 5 years :P) but I would rather get a refresher from one of you guys/gals

    The problem involves trying to find the height of water in an open channel given the rate of flow and channel cross section. y is the height of water in question.

    Thanks!
    Follow Math Help Forum on Facebook and Google+

  2. #2
    MHF Contributor
    Joined
    Sep 2012
    From
    Australia
    Posts
    4,026
    Thanks
    741

    Re: Solving an equasion Implicitly, Hydraulics Question

    Hey CivilEngineer1988.

    Is a numerical approximation OK for your purposes (i.e. to so many decimal places)?
    Follow Math Help Forum on Facebook and Google+

  3. #3
    Member
    Joined
    Aug 2011
    Posts
    249
    Thanks
    60

    Re: Solving an equasion Implicitly, Hydraulics Question

    Hi CivilEngineer1988 !
    Don't you see that ((y+2*y^2)/(2.236+4.472*y)) = y/2.236 ?
    0.33392=(1/0.027)*(y/2.236)^(2/3)
    y = 2.236*(0.33392*0.027)^(3/2) = 0.00191417
    Follow Math Help Forum on Facebook and Google+

  4. #4
    MHF Contributor
    Joined
    Sep 2012
    From
    Australia
    Posts
    4,026
    Thanks
    741

    Re: Solving an equasion Implicitly, Hydraulics Question

    Very nice: I'm glad someone is paying attention
    Follow Math Help Forum on Facebook and Google+

  5. #5
    Member
    Joined
    Aug 2011
    Posts
    249
    Thanks
    60

    Re: Solving an equasion Implicitly, Hydraulics Question

    Sorry, there is something wrong in my precceding answer, because I consider the equation :
    0.33392=(1/0.027)*((y+2*y^2)/(2.236+4.472*y))^(2/3)
    instead of :
    0.33392=(1/0.027)*(y+2*y^2)*((y+2*y^2)/(2.236+4.472*y))^(2/3)
    So, after simplification, the equation is not :
    0.33392=(1/0.027)*(y/2.236)^(2/3)
    but :
    0.33392=(1/0.027)*(y+2*y^2)*(y/2.236)^(2/3)
    0.33392*0.027*2.236^(2/3) = (1+2y)*y^(5/3)
    which can be solved thanks to numerical computation, as chiro suggested first.

    y = 0.075210480866976
    Last edited by JJacquelin; January 22nd 2013 at 02:29 AM.
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Simplify Expression for Hydraulics
    Posted in the Algebra Forum
    Replies: 1
    Last Post: December 14th 2011, 12:41 PM
  2. Replies: 9
    Last Post: November 30th 2011, 04:30 PM
  3. graph an equasion with no y
    Posted in the Algebra Forum
    Replies: 1
    Last Post: February 13th 2011, 01:12 PM
  4. Prove the following equasion:
    Posted in the Trigonometry Forum
    Replies: 4
    Last Post: December 16th 2010, 06:37 AM
  5. equivalent equasion
    Posted in the Algebra Forum
    Replies: 1
    Last Post: July 7th 2007, 03:00 PM

Search Tags


/mathhelpforum @mathhelpforum