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+//Example 6.8
+// Nyquist plot for a second order system.
+
+xdel(winsid())//close all graphics Windows
+clear;
+clc;
+//------------------------------------------------------------------
+//System transfer function and its root locus
+s=poly(0,'s');
+g=1/(s+1)^2;
+sysG=syslin('c',g);
+
+evans(sysG);
+exec .\fig_settings.sci; //custom script for setting figure properties
+f=gca();
+f.x_location = "origin"
+f.y_location = "origin"
+title(['Root locus of','$G(s)=1/(s+1)^2$','with respect to K'],...
+'fontsize',3)
+zoom_rect([-3,-2,2,3])
+h=legend('');
+h.visible = "off"
+//------------------------------------------------------------------
+figure(1)
+//The bode plot of the system
+fmin=0.01/2/%pi; //mininmum frq. in Hz for response (0.1 rad/sec)
+fmax=100/2/%pi; //maximum frq. in Hz for response (100 read/sec)
+
+//Bode plot for frequency in Hz (scilab ver. 5.4.1)
+//bode(g,fmin,fmax); 
+//OR 
+//Bode plot for frequency in rad/sec (scilab ver. 5.5.1)
+bode(sysG,fmin,fmax,0.01,"rad") 
+title(['Open loop bode plot for', '$G(s)=1/(s+1)^2$'],'fontsize',3);
+exec .\fig_settings.sci; //custom script for setting figure properties
+//------------------------------------------------------------------
+
+figure(2)
+//The nyquist plot of the system
+nyquist(sysG);
+title('Nyquist plot of the evaluation of K G(s) for s=C1 and K=1'...
+,'fontsize',3);
+exec .\fig_settings.sci; //custom script for setting figure properties
+f=gca();
+f.x_location = "origin"
+f.y_location = "origin"
+xset('color',2)
+//------------------------------------------------------------------