Equation ... finding x

t*s*

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Feb 4, 2012
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Øᵥ=(b*b*x)/u *〖((b*b*x)/(b+2b*x))〗^(2/3) *√y ... I have this equation and I solved it to this point Øᵥ*u/(b^2*√y*b^(2/3))=x*(x/(1+2x))^(2/3) ... and now I do not know how to continue (finding x)... could someone please help me
 
Hello, t*s*!

I don't think it can be done . . .



\(\displaystyle \phi \;=\; \dfrac{b^2x}{u} \cdot \left(\dfrac{b^2x}{b+2bx}\right)^{\frac{2}{3}}\cdot\sqrt{y} \qquad \text{ Solve for }x. \)

\(\displaystyle \text{We have: }\:\phi \;=\;\dfrac{b^2x}{u}\cdot\left(\dfrac{b^2x}{b(1+2x)}\right)^{\frac{2}{3}}\cdot \sqrt{y}\)

. . . . . . . . \(\displaystyle \displaystyle \phi \;=\;\frac{b^2x}{u}\cdot\frac{b^{\frac{4}{3}}x^{\frac{2}{3}}}{b^{\frac{2}{3}}(1+2x)^{\frac{2}{3}}}\cdot \sqrt{y} \)

. . . . . . . . \(\displaystyle \displaystyle \phi \;=\;\frac{b^{\frac{8}{3}}x^{\frac{5}{3}}y^{\frac{1}{2}}}{u(1+2x)^{\frac{2}{3}}} \)

. . . . . . . . \(\displaystyle \phi u (1+2x)^{\frac{2}{3}} \;=\;b^{\frac{8}{3}}y^{\frac{1}{2}}x^{\frac{5}{3}} \)


I see no way to solve for \(\displaystyle x\).
 
If you "cube" both sides - then you would get a "quintic" and there is no general analytic (closed form) solution for those types of equations.
 
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