Question: weird error that I don't understand

February 01 2013 woofwoof 15

0

Hi in trying to solve these coupled differential equations i get a weird error:

 

> t := diff(X(x), x) = -(1-6*R(x)^(1/2))^(1/2)*x*X(x)/(X(x)*x+R(x))^(1/2), diff(R(x), x) = (1-6*R(x)^(1/2))^(1/2)*x^2*X(x)/(X(x)*x+R(x))^(1/2);
(1/2)
/ (1/2)\
d \1 - 6 R(x) / x X(x)
--- X(x) = - -----------------------------,
dx (1/2)
(X(x) x + R(x))

(1/2)
/ (1/2)\ 2
d \1 - 6 R(x) / x X(x)
--- R(x) = ------------------------------
dx (1/2)
(X(x) x + R(x))
> init(R(0) = 0, X(0) = 100);
init(R(0) = 0, X(0) = 100)
> Solve({t, init});
Error, (in PDEtools:-casesplit) the input system cannot contain equations in the arbitrary parameters alone; found equation: init
 
I am using PDE tools, please can someone help.
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