text: Hi,
  
  I'm having trouble solving this equation.. I know it is supposed to turn out a quadratic equation, but I just can't do the math.. Would be incredibly grateful if anyone could help!!
  
  Here it goes:
  
  0,6 = √(Wa*0,4390)^2 + (Wb*0,8235)^2 + 2*(Wa*0,4390)*(Wb*0,8235)*0,253454
  
  Now the squareroot is supposed to cover the entire right side of the equation. Wa and Wb are unknowns.
  
  2. Are you looking to solve for them numerically or in terms of each other? As far as I know if you only have one equation and yet two unkowns you cannot solve for them numerically. Someone could correct me though.
  
  Anyway, numerically.. Sorry, I forgot to replace Wb with 1-Wa.. What I'm trying to do here is find unknown weights in a portfolio of two assets. Since Wa + Wb = 1, Wb = 1-Wa.
  For simplicity, I replaced Wa with X.
  
  Here is the new equation:
  
  0,6 = √(X*0,4390)^2+((1-X)*0,8235)^2+2*(X*0,4390)*((1-X)*0,8235)*0,253454
  
  4. Oh ok, I'd square both sides, expand all of your brackets, collect like terms. Bring all terms to one side, so the other side is zero and then apply the quadratic formula.
  
  5. Originally Posted by cupcake
  Anyway, numerically.. Sorry, I forgot to replace Wb with 1-Wa.. What I'm trying to do here is find unknown weights in a portfolio of two assets. Since Wa + Wb = 1, Wb = 1-Wa.
  For simplicity, I replaced Wa with X.
  
  Here is the new equation:
  
  0,6 = √(X*0,4390)^2+((1-X)*0,8235)^2+2*(X*0,4390)*((1-X)*0,8235)*0,253454
  Try replacing:
  
  √(X*0,4390)^2
  
  by
  
  X*0,4390
  
  and then simplifying
  
  CB
  
  6. Originally Posted by CaptainBlack
  Try replacing:
  
  √(X*0,4390)^2
  
  by
  
  X*0,4390
  
  and then simplifying
  
  CB
  But I think he said in his original post that the square root covers the entire RHS
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