Write Matlab code for Numerical Differentiation using Newton Forward, Backward, and Lagranges formulas?

Fun = @(x) exp(-x).*sin(3*x);

dFun = @(x) -exp(-x).*sin(3*x)+ 3*exp(-x).*cos(3*x);

x=linspace(0,4,101);

F=Fun(x);

h=x(2)-x(1);

xCentral=x(2:end-1);

dFCenteral=(F(3:end)-F(1:end-2))/(2*h);

xForward=x(1:end-1);

dFForward=(F(2:end)-F(1:end-1))/h;

xBackward=x(2:end);

dFBackward=(F(2:end)-F(1:end-1))/h;

plot(x,dFun(x));

hold on

plot(xCentral,dFCenteral,'r')

plot(xForward,dFForward,'k');

plot(xBackward,dFBackward,'g');

legend('Analytic','Central','Forward','Backward')

[John D'Errico]

What is your question? if your code works, then why are you posting your homework? So you must have a question in this somewhere.

[Muhammad Owais]

Actually, I need separate codes for forward, backward and lagrange formula of numerical differentiation.

[Muhammad Owais]

Not for plot, but to run the codes