I am using code from adress http://matlab.cheme.cmu.edu/2011/09/08/plane-poiseuille-flow-bvp-solve-by-shooting-method//
but every time when I want to execute it I got:
'Undefinied function 'exist' for input arguments of type 'symfun'.
Error in odearguments line 59, if (exist(ode)==2).
Error in ode45 line 113 [neq,tspan,ntsoan,next,t0,tfinal,tdir...]
I have not idea what to do? I checked, my matlab version has symbolic mathtoolbox.