clc
clear

T=0.1;

numc=[10 1];
denc=[1   1];

csys=tf(numc,denc)




num_eu=[10 -10+T];
den_eu=[1   -1+T];
eu_sys=tf(num_eu,den_eu,T)


num_bk=[10+T -10];
den_bk=[1+T   -1];
bk_sys=tf(num_bk,den_bk,T)


num_t=[20+T -20+T];
den_t=[2+T   -2+T];
t_sys=tf(num_t,den_t,T)


bode(csys, eu_sys, bk_sys, t_sys)
legend('Continous', 'Euler Approx', 'Backward Approx','Tustin')
% axis([0.01   10   -100   100])