5.1

x=-4:0.1:4 y=（sin(x).^2）./(1+x.^2); plot(x,y)

5.2

v = 100; g = 9.8; x = 0:1200; for a = [30 45 75] y = x.*tan(a/360)-g*x.^2/(2*v^2*cos(a/360)^2); if a == 30 plot(x,y,'r-') hold on elseif a == 45 plot(x,y,'b-') hold on elseif a == 75 plot(x,y,'y-') hold on end end

5.3

zeta = 0:0.1:2*pi; r = -cos(2*zeta).*sec(zeta); [x,y] = pol2cart(zeta,r); subplot(1,2,1); polar(zeta,r) subplot(1,2,2); plot(x,y) grid on