clear;
m=1;c=2;k=3;
t=0:0.01:10;
cmk=(c^2-4*m*k)^0.5;
y=m/cmk*(exp(-(c-cmk)/2/m*t)-exp(-(c+cmk)/2/m*t));
plot(t,y);
grid('on');
xlabel('Time[s]');ylabel('Response');