x = linspace(0, pi/2, 100);

for n=1:10 
  plot(x,n*cos(x)./(n+sin(x))) 
  hold on 
end
plot(x,cos(x),'r')

clf reset

x = linspace(0, 1, 300);
for n=1:50 
  plot(x,2*x.*(1+n*exp(-n*x.^2))) 
  hold on
end
plot(x,2*x,'r','LineWidth',2)