Results 1 to 5 of 5

Math Help - solving systems of equations

  1. #1
    Junior Member
    Joined
    Nov 2009
    Posts
    73

    solving systems of equations

    solve the following for u and t

    x= u + t^2

    y = t - u^2
    Follow Math Help Forum on Facebook and Google+

  2. #2
    Senior Member
    Joined
    Feb 2008
    Posts
    383
    Quote Originally Posted by scubasteve123 View Post
    solve the following for u and t

    x= u + t^2

    y = t - u^2
    u=x-t^2

    sub 1st equation into 2nd equation

    y=t-(x-t^2)^2

    then simplify.
    Follow Math Help Forum on Facebook and Google+

  3. #3
    Junior Member
    Joined
    Nov 2009
    Posts
    73
    I tried this and was just left with y + x^2 = t +2xt^2 - t^4

    ... not sure how to simplify this I just end up going in circles with all the substitution.
    Follow Math Help Forum on Facebook and Google+

  4. #4
    Senior Member
    Joined
    Feb 2008
    Posts
    383
    Quote Originally Posted by scubasteve123 View Post
    I tried this and was just left with y + x^2 = t +2xt^2 - t^4

    ... not sure how to simplify this I just end up going in circles with all the substitution.
    you are right what you are doing.

    after you simplfy you get:

    y=t-x^2+2t^2x-t^4

    well we need to rearrange it a little bit, so we get:

    y=-x^2+2t^2x+(t-t^4)

    then using the Quadratic equation



    we sub in the numbers,

    \frac{-2t^2\pm\sqrt{(2t^2)^2-4*-1*(t-t^4)}}{2*-1}=0

    then again simplfy:

    \frac{-2t^2\pm\sqrt{4t}}{-2}=0

    so we get t=1 or t=0

    if t=0 x=0

    if t=1 x=2 or 0.

    hope this helps. correct me if im wrong anyone.
    Follow Math Help Forum on Facebook and Google+

  5. #5
    Super Member Bacterius's Avatar
    Joined
    Nov 2009
    From
    Wellington
    Posts
    927
    You can simplify even further, Babymilo :

    \frac{-2t^2\pm\sqrt{4t}}{-2}=0

    Extract the 4 from the square root :

    \frac{-2t^2\pm 2 \sqrt{t}}{-2}=0

    Factorize 2 :

    \frac{2(-t^2 \pm \sqrt{t})}{-2}=0

    Cancel out the 2 :

    \frac{-t^2 \pm \sqrt{t}}{-1}=0

    Finally :

    t^2 \mp \sqrt{t} = 0
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Solving systems of equations help
    Posted in the Pre-Calculus Forum
    Replies: 2
    Last Post: March 9th 2012, 08:30 AM
  2. Replies: 6
    Last Post: November 30th 2011, 02:41 AM
  3. Solving systems of equations
    Posted in the Algebra Forum
    Replies: 3
    Last Post: December 7th 2009, 02:45 PM
  4. Solving Systems of Equations
    Posted in the Algebra Forum
    Replies: 1
    Last Post: February 18th 2008, 02:07 AM
  5. solving systems of equations
    Posted in the Algebra Forum
    Replies: 5
    Last Post: October 9th 2006, 09:46 PM

Search Tags


/mathhelpforum @mathhelpforum