solving diffrential equation systems

Hello everybody I want to solve this series of diffrential equation and everytime matlab types an eror what should I do please somebody help me v1=1000; v2=1500; v3=100; k1=.1; k2=.2; k3=.4; syms f(t) g(t) y(t) S=dsolve(diff(f)==((1/v1)*(1000+100*g-1100*f-k1*v1*f)),diff(g)==((1/v2)*(1100*f-1100*g-k2*v2*g)),diff(y)==((1/v3)*(1000*g-1000y-k3*v3*y)) and f(0) and g(0) and y(0) are all zero

Answer 1

[Torsten]

What exactly is the error message ?

Best wishes

Torsten.

[mohsen safaei]

hello this is the eror | Error: Unexpected MATLAB expression.

[Torsten]

Maybe because there is a parenthesis missing behind the expression

S=dsolve(diff(f)==((1/v1)*(1000+100*g-1100*f-k1*v1*f)),diff(g)==((1/v2)*(1100*f-1100*g-k2*v2*g)),diff(y)==((1/v3)*(1000*g-1000y-k3*v3*y))

?

Best wishes

Torsten.

Answer 2

[VBBV]

v1=1000; 
v2=1500; 
v3=100; 
k1=.1; k2=.2; k3=.4; 
syms f(t) g(t) y(t)
eq1 = diff(f)==((1/v1)*(1000+100*g-1100*f-k1*v1*f))

eq1(t) = 

eq2 = diff(g)==((1/v2)*(1100*f-1100*g-k2*v2*g))

eq2(t) = 

eq3 = diff(y)==((1/v3)*(1000*g-1000*y-k3*v3*y))  % use the multiplication operator 

eq3(t) = 

S=dsolve([eq1 eq2 eq3])

S = struct with fields:
    g: exp((t*(82^(1/2) - 32))/30)*(82^(1/2)/300 + 14/15)*(C2 - (5500*exp(-(t*(82^(1/2) - 32))/30)*(140*82^(1/2) - 41))/(178391*(82^(1/2) - 32))) - exp(-(t*(82^(1/2) + 32))/30)*(82^(1/2)/300 - 14/15)*(C3 - (5500*exp((t*(82^(1/2) + 32))/30)*(140*82^(1/…
    f: exp((t*(82^(1/2) - 32))/30)*((23*82^(1/2))/550 - 173/1100)*(C2 - (5500*exp(-(t*(82^(1/2) - 32))/30)*(140*82^(1/2) - 41))/(178391*(82^(1/2) - 32))) - exp(-(t*(82^(1/2) + 32))/30)*((23*82^(1/2))/550 + 173/1100)*(C3 - (5500*exp((t*(82^(1/2) + 32))…
    y: exp((t*(82^(1/2) - 32))/30)*(C2 - (5500*exp(-(t*(82^(1/2) - 32))/30)*(140*82^(1/2) - 41))/(178391*(82^(1/2) - 32))) + exp(-(t*(82^(1/2) + 32))/30)*(C3 - (5500*exp((t*(82^(1/2) + 32))/30)*(140*82^(1/2) + 41))/(178391*(82^(1/2) + 32))) + exp(-(52…