Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

How to solve (x-1)^2 * (a+x)=1

  1. Jan 21, 2009 #1
    I am a little bit confused about solving the following equation:


    How to do this??
  2. jcsd
  3. Jan 21, 2009 #2
    Are you sure there's a simple way to solve that, given that you don't know a? It's a cubic...
  4. Jan 21, 2009 #3
    well, actually this is the original equation (see figure1)

    The solution is in figure 2..

    So let me reformulate my question: Can this be proven analytically?

    Attached Files:

  5. Jan 21, 2009 #4


    User Avatar
    Homework Helper
    Gold Member

    This is very different from the problem in your first post!

    Anyways, start by squaring both sides of the equation in the first link. Then multiply both sides by [tex]4((\rho^{*})^2+(x^{*})^2)[/tex] and simplify to obtain:


    That should tell you that either [tex](\rho^{*})^2=0[/tex] or


    You can use the quadratic equation to solve the above expression for [tex](\rho^{*})^2[/tex] and then take the square root to obtain the final solution.
  6. Jan 22, 2009 #5
    Yes, ok thank you. It did not cross my mind to substitute a variable for a variable^2
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook