dx1/dt=(p7*p4*x9)/p6+p1*x1*u1;
dx2/dt=-2*p2*x2^2;
dx3/dt=p2*x2^2-p3*x3;
dx4/dt=-(p7*p4*x4-p6*p3*x3)/p7;
dx5/dt=-p4*(x5-2*x4);
dx6/dt=p4*(x5-x6);
dx7/dt=p4*(x6-x7);
dx8/dt=p4*(x7-x8);
dx9/dt=p4*(x8-x9);
y1=(x2+2*x3)/p5;
y2=(x1+x2+2*x3)/p5;
