a = 25;

f = @(x) 1./(1+a*x.^2); % runge's phenomena
f1 = @(x) -2*a*x./(1+a*x.^2);
f2 = @(x) 2*a*(3*a*x.^2-1)./(1+a*x.^2).^3;
f3 = @(x) 24*a^2*x.*(a*x.^2-1)./(1+a*x.^2).^4;
f4 = @(x) (24*a^2*(5*a^2.*x.^4 - 10*a*x.^2 + 1))./(a*x.^2 + 1).^5;

x = linspace(-2,2,10000);
plot(x,f(x))
hold on
plot(x,f1(x))
plot(x,f2(x))
plot(x,f3(x))
plot(x,f4(x))

legend('f(x)','First derivative','Second derivative','Third derivative','Fourth derivative')