ode15s differential-algebraic problem

Hi. I have to solve

and

but I do not get the solution I was supposed to. Could you please tell me if my code is correct? Thank you.

convezione.m file

function out = convezione(t,y)
out = [y(2)
   1/y(1)*(-1.5*y(2)^2 + y(2)/y(3) + sin(t))
   1/y(1)*((y(2)/y(3))^(1/3) + y(2)/y(3)) - y(3) ];

runconv.m file

function runconv
y0 = [1; 1; 1];
[t,y] = ode15s(@convezione,[0 10],y0);
plot(t,y(:,1))

Answer 1

[Torsten]

Try

function out = convezione(t,y)
out = [y(2)
   1/y(1)*(-1.5*y(2)^2 + y(2)/y(3) + sin(t))
   1/y(1)*((y(2)/y(3))^(1/3) + y(1)/y(3)) - y(3) ];

function runconv
y0 = [1; 1; 1.3247^1.5];
[t,y] = ode15s(@convezione,[0 10],y0);
plot(t,y(:,1))

Best wishes

Torsten.

Answer 2

[Torsten]

Sorry, the code was wrong.

Use

function out = convezione(t,y)
out = [y(2)
   1/y(1)*(-1.5*y(2)^2 + y(2)/y(3) + sin(t))
   1/y(1)*((y(2)/y(3))^(1/3) + y(1)/y(3)) - y(3) ];

function runconv
y0 = [1; 1; 1.3247^1.5];
M = [1 0 0; 0 1 0; 0 0 0];
options = odeset('Mass',M);
[t,y] = ode15s(@convezione,[0 10],y0,options);
plot(t,y(:,1))

Best wishes

Torsten.