Hi everyone 

I want to solvethe following  differential equation system:

> equa1 := c[pa]*L*(diff(T[air](t), t)) = h*(T[sol](t)-T[air](t))+L*L[vap]*(diff(m[v0]-709.2750000*M*exp(1.000000000*10^(-8)*(1.311709131*10^9*T[air](t)-4.892675059*10^11)/T[air](t))/(R*T[air](t)), t));
> equa2 := c[ps]*l*(diff(T[sol](t), t)) = h*(T[air](t)-T[sol](t))-exp(-opt*L*(m[v0]-709.2750000*M*exp(1.000000000*10^(-8)*(1.311709131*10^9*T[air](t)-4.892675059*10^11)/T[air...