cannot find explicit solution symbolic equation
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Hi!
I have a an equation with symbolics characters, and i want an expression for one of them ( lamb1 in the present case) but when i use the " solve(t==0,lamb1)" anyway i tried, i can't solve it! It says : "Warning: Cannot find explicit solution. > In solve (line 316)"
my vector t is : ( for the equation t=0 )
t =
0;
(sin(theta)*(2*lamb3^(beta - 1)*nu - (2*nu*(lamb1*lamb3^2)^(beta/3))/lamb3 + 2*kappa*lamb1*lamb3*(lamb1*lamb3^2 - 1)^(gamma - 1)))/pho0;
(cos(theta)*(2*lamb3^(beta - 1)*nu - (2*nu*(lamb1*lamb3^2)^(beta/3))/lamb3 + 2*kappa*lamb1*lamb3*(lamb1*lamb3^2 - 1)^(gamma - 1)))/pho0;
So it's not quiet simple. Is there something wrong in what i do ?
Any idea to solve it ? Thank you !
2 comentarios
John D'Errico
el 11 de Abr. de 2016
Sorry. It is simply never going to be possible to do what you want. It is trivial to write down a set of equations for which no analytical solution will ever be possible. Just wanting it to work is not sufficient.
Respuestas (2)
Roger Stafford
el 11 de Abr. de 2016
Editada: Roger Stafford
el 11 de Abr. de 2016
You have what appears to be two equations but only one unknown, namely 'lamb1'. You might try listing 'lamb3' as a second unknown and see what happens. There is no guarantee that 'solve' can solve that either because of the complexity of those equations.
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Walter Roberson
el 11 de Abr. de 2016
You have lamb1 to the power of the unknown parameter (gamma - 1) . In order to solve that for an explicit solution, there would have to be a closed form method of solving all polynomials of all degrees -- for example, gamma might be 148 so you would need a closed form formula able to explicitly solve polynomials of degree (148-1) = 147. And the formula would have to be valid for all possible integer powers, and for all possible floating point powers as well. It has been proven (Able-Ruffini Theorem) that no such closed formula can possibly exist for polynomials of degree 5 or higher. It is therefore impossible to find an explicit solution to this equation.
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