g(s):=(1+3*s)/((1+4*s)*(1+2*s)); define(angle(w),(180/%pi)*atan(ratsimp(imagpart(g(%i*w))/realpart(g(%i*w))))); plot2d(angle, [w,0.01,10],[gnuplot_preamble, "set log x;set grid"]);

g(s):=(1+3*s)/((1+4*s)*(1+2*s)); define(angle(w),(180/%pi)*atan(ratsimp(imagpart(g(%i*w))/realpart(g(%i*w))))); plot2d(angle, [w,0.01,10],[gnuplot_preamble, "set log x;set grid"]);