Results 1 to 6 of 6

Math Help - Rewriting function equation

  1. #1
    Member
    Joined
    Dec 2006
    Posts
    93
    Awards
    1

    Rewriting function equation

    Rewrite the equation y = 2x 4 as a function of x.

    Please rtell me this is right.....

    y + 4 = -2x
    Follow Math Help Forum on Facebook and Google+

  2. #2
    is up to his old tricks again! Jhevon's Avatar
    Joined
    Feb 2007
    From
    New York, USA
    Posts
    11,663
    Thanks
    3
    Quote Originally Posted by Patience View Post
    Rewrite the equation y = –2x – 4 as a function of x.

    Please rtell me this is right.....

    y + 4 = -2x
    not completely. a function of x means we want x ONLY on one side of the equal sign.

    so

    y = –2x – 4
    => -2x = y + 4 ..........you were right up to here
    => x = (y + 4)/-2 ......divide both sides by -2
    => x = (-1/2)y - 2
    Follow Math Help Forum on Facebook and Google+

  3. #3
    Grand Panjandrum
    Joined
    Nov 2005
    From
    someplace
    Posts
    14,972
    Thanks
    4
    Quote Originally Posted by Patience View Post
    Rewrite the equation y = 2x 4 as a function of x.

    Please rtell me this is right.....

    y + 4 = -2x
    Writing this as a function of x would usually require something like:

    y=f(x),

    where f:x in R -> -2x -4

    or alternatively y(x)=-2x -4.

    RonL
    Follow Math Help Forum on Facebook and Google+

  4. #4
    is up to his old tricks again! Jhevon's Avatar
    Joined
    Feb 2007
    From
    New York, USA
    Posts
    11,663
    Thanks
    3
    Quote Originally Posted by CaptainBlack View Post
    Writing this as a function of x would usually require something like:

    y=f(x),

    where f:x in R -> -2x -4

    or alternatively y(x)=-2x -4.

    RonL
    well that's true, but i just figure she made a typo or phrased the question incorrectly.

    afterall, what self-respecting math book would give a problem where the solution is just to add (x) on one side? seems trivial to me
    Follow Math Help Forum on Facebook and Google+

  5. #5
    Grand Panjandrum
    Joined
    Nov 2005
    From
    someplace
    Posts
    14,972
    Thanks
    4
    Quote Originally Posted by Jhevon View Post
    well that's true, but i just figure she made a typo or phrased the question incorrectly.

    afterall, what self-respecting math book would give a problem where the solution is just to add (x) on one side? seems trivial to me
    Yes, but I can't let misuse of mathematical language go without comment.

    Seeing as you have already answered the question that was probably
    intended it is of some importance to show that the question as asked
    means something entirely different.

    RonL
    Follow Math Help Forum on Facebook and Google+

  6. #6
    is up to his old tricks again! Jhevon's Avatar
    Joined
    Feb 2007
    From
    New York, USA
    Posts
    11,663
    Thanks
    3
    Quote Originally Posted by CaptainBlack View Post
    Yes, but I can't let misuse of mathematical language go without comment.

    Seeing as you have already answered the question that was probably
    intended it is of some importance to show that the question as asked
    means something entirely different.

    RonL
    agreed
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Replies: 2
    Last Post: November 21st 2010, 04:19 AM
  2. Rewriting an equation.
    Posted in the Algebra Forum
    Replies: 5
    Last Post: March 31st 2010, 08:01 PM
  3. Rewriting equation
    Posted in the Algebra Forum
    Replies: 1
    Last Post: December 2nd 2009, 11:56 AM
  4. Rewriting Equation
    Posted in the Calculus Forum
    Replies: 1
    Last Post: August 30th 2009, 11:24 AM
  5. Rewriting an equation
    Posted in the Algebra Forum
    Replies: 2
    Last Post: October 23rd 2008, 10:22 AM

Search Tags


/mathhelpforum @mathhelpforum