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