any help please ?
Hello, i face problem trying to solve the following differential algebraic equation system:
d(x1)=f1(x1,t)
d(x2)=f2(x2,t)
d(x3)=f3(x3,t)
d(x4)=f4(x4,x5,t)
d(x5)=f5(x4,x5,x6,t,z)
d(x6)=f6(x5,x6,t)
g(x1,x2,x3,t)=0 =>x1(t)+x2(t)+x3(t)=C(constant value) (specifically this is the algebraic function g analytically)
h(x1,x2,x3,x4,x5,t,z)=0 (algebraic function h is more complicated, it includes log function also between the unknown variables)
If you could give me a method to solve it , i would be gratefull.
Till now i'm using numerical analysis to solve it (using ode23 function from matlab), but i do not know how to solve the differential equations in parallel with the algebraic ones.
Thank you in advance
I'm giving more info about the variables and the structure of the problem.
K1*(d(x1)/dt)=K2*K3-K4*x1(t)+K5
K1*(d(x2)/dt)=K2*K6-K4*x2(t)-0.5*K5
K1*(d(x3)/dt)=K2*K6-K4*x3(t)
K1*(d(x4)/dt)=K2*K7-K4*x4(t)+K8*(x5(t)-x4(t))
K9*(d(x5)/dt)=K10*(x4(t)-x5(t))+K11*(x6(t)-x5(t))+K12*(K13-x5(t))+Q*K14
K15*(d(x6)/dt)=K16*(K17-x6(t))+K18*(x5(t)-x6(t))
g(x1,x2,x3,t)=0 =>x1(t)+x2(t)+x3(t)=C(constant value)
C=(0.5*K5)/(K4-K2)
Q=K18-K19*[K20+K21*x5(t)*ln(K22*(x2(t)*x4(t))^(0.5))/(x1(t)*x4(t))-K23*x4(t)
-K24+K25*x4(t)*ln(K26/x2(t))]
All Ki (i=1-26) variables are constant and independent.