Hello,

I am trying to solve the following differential coupled system :

DN:=diff(N(x),x)=a/4*(x+8*(sin(F(x)))^2/x)*N(x)*diff(F(x),x)^2;

Du:=diff(u(x),x)=a/8*((x^2+8*(sin(F(x)))^2)*(1-u(x)/x)*diff(F(x),x)^2+2*(sin(F(x)))^2+4*(sin(F(x)))^4/x^2);

DDF:=diff(F(x),x$2)=1/(N(x)*(1-u(x)/x)*(x^2+8*(sin(F(x)))^2))*(-(x^2+8*(sin(F(x)))^2)*diff(N(x),x)*(1-u(x)/x)*diff(F(x),x)+(1+4*(sin(F(x)))^2/x^2+4*(1-u(x)/x)*diff(F(x),x)^2)*N(x)*sin(2*F(x...