-->	f1(x):=3*sqrt(-(x/7)^2*sqrt(abs(abs(x)-3)/(abs(x)-3))+1);

-->	f2(x):=-3*sqrt(-(x/7)^2*sqrt(abs(abs(x)-4)/(abs(x)-4))+1);

-->	f3(x):=abs(x/2)-(3*sqrt(33)-7)/112*x^2+sqrt(1-(abs(abs(x)-2)-1)^2)-3;

-->	f4(x):=9*sqrt(abs((abs(x)-1)*(abs(x)-0.75))/((1-abs(x))*(abs(x)-0.75)))-8*abs(x);

-->	f5(x):=3*abs(x)+0.75*sqrt(abs((abs(x)-0.75)*(abs(x)-0.5))/((0.75-abs(x))*(abs(x)-0.5)));

-->	f6(x):=2.25*sqrt(abs(abs(x)-0.5)/(0.5-abs(x)));

-->	f7(x):=6*sqrt(10)/7+(1.5-0.5*abs(x))*sqrt(abs(abs(x)-1)/(abs(x)-1))-6*sqrt(10)/14*sqrt(4-(abs(x)-1)^2);

-->	wxplot2d([f1(x),f2(x),f3(x),f4(x),f5(x),f6(x),f7(x)], [x,-7,7], [y,-3,3],[legend,false])$

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Created with wxMaxima.