Results 1 to 3 of 3

Math Help - Find x as a function of y

  1. #1
    Junior Member
    Joined
    Mar 2010
    Posts
    41

    Find x as a function of y

    I have to express x as a function of y in the equation:

    y=x/(1-x)

    The back of the book says that the answer is y/(1+y). I'm really stuck on how they got there.
    Follow Math Help Forum on Facebook and Google+

  2. #2
    Flow Master
    mr fantastic's Avatar
    Joined
    Dec 2007
    From
    Zeitgeist
    Posts
    16,948
    Thanks
    5
    Quote Originally Posted by blackdragon190 View Post
    I have to express x as a function of y in the equation:

    y=x/(1-x)

    The back of the book says that the answer is y/(1+y). I'm really stuck on how they got there.
    y(1 - x) = x

    => y - yx = x

    => y = x + yx = x(y + 1)

    => y/(y + 1) = x.
    Follow Math Help Forum on Facebook and Google+

  3. #3
    Newbie
    Joined
    Mar 2010
    Posts
    4
    Quote Originally Posted by blackdragon190 View Post
    I have to express x as a function of y in the equation:

    y=x/(1-x)

    The back of the book says that the answer is y/(1+y). I'm really stuck on how they got there.
    I'll explain what he did^^^ Basically "x is a function of y" means the value of x depends on the value of y.

    The equation y=x/(1-x) is solved for y, and you can't determine what the value of x would be if you were to know y. So all you do is solve for x by moving everything around as shown in the post above.

    properly it would be f(y)=y/(y+1)
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. find all function
    Posted in the Number Theory Forum
    Replies: 0
    Last Post: September 27th 2011, 10:24 AM
  2. Find function
    Posted in the Number Theory Forum
    Replies: 5
    Last Post: April 19th 2011, 05:04 AM
  3. Replies: 14
    Last Post: January 18th 2010, 07:16 PM
  4. find function
    Posted in the Pre-Calculus Forum
    Replies: 1
    Last Post: September 8th 2008, 03:22 PM
  5. Replies: 3
    Last Post: July 17th 2007, 12:06 PM

Search Tags


/mathhelpforum @mathhelpforum