function g=gfunc(gam);
y0=zeros(2,1);
t0=1.0;
tfinal=3.0;
y0(1)=17.0;
y0(2)=gam;
[t,y] = ode45('sistema',[t0,tfinal],y0);
[m,n]=size(y);
g=y(m,1)-43/3;