mat-3.m

function yp=derivadanolin(t,y)

global L m P k c



yp(1,1)=y(3);
yp(2,1)=y(4);
yp(3,1)=(P*L*sin(y(1)-y(2))-k*y(1)-c*y(3)-0.5*m*L^2*y(4)^2*sin(y(1)-y(2))...
    +1.5*k*cos(y(1)-y(2))*y(2)+1.5*c*cos(y(1)-y(2))*y(4)-1.5*y(3)^2*...
    sin(y(1)-y(2))*0.5*m*L^2*cos(y(1)-y(2)))*(12/((16-9*(cos(y(1)-y(2)))^2)*m*L^2));
yp(4,1)=(0.5*m*L^2*y(3)^2*sin(y(1)-y(2))-k*y(2)-c*y(4)-0.5*m*L^2*yp(3)*cos(y(1)-y(2)))...
    *(3/(m*L^2));