TS2

clear
clc
syms s z
u=(s+1)*(s+10)*(s+15);
%u=4*z^4-3*z^3+2*z^2+5;
rad_s=0;
rad_z=0;
rad_s=double(solve(u,s));
%rad_z=double(solve(u,z));
k=0;
if(rad_s~=0)
for i=1:length(rad_s)
    if(rad_s(i)<0)
disp(['s',num2str(i),'=',num2str(rad_s(i)),' < 0'])
    elseif(rad_s(i)==0)
disp(['s',num2str(i),'=',num2str(rad_s(i)),' = 0 => marginal stabil'])
    elseif(rad_s(i)>0)
disp(['s',num2str(i),'=',num2str(rad_s(i)),' > 0 => instabil'])
    end
end
for i=1:length(rad_s)
if(rad_s(i)==0)
    k=-1;
elseif(rad_s(i)>0)
    k=-2;
    break
end
end
switch k
    case 0
        disp('s - asimptotic stabil')
    case -1
        disp('s - marginal stabil')
    case -2
        disp('s - instabil')
end
end
k=0;
if(rad_z~=0)
for i=1:length(rad_z)
disp(['|z',num2str(i),'|=',num2str(abs(rad_z(i)))])
end
for i=1:length(rad_z)
if(abs(rad_z(i))==1)
    k=-1;
elseif(abs(rad_z(i))>1)
    k=-2;
    break
end
end
switch k
    case 0
        disp('z - asimptotic stabil')
    case -1
        disp('z - marginal stabil')
    case -2
        disp('z - instabil')
end
end