MATLAB Answers

first forward and backward central diference

3 views (last 30 days)
Adam
Adam on 23 Apr 2012
Hi, I have a task to do by diference of those formulas someone help me? input values are specified they get when I have done.
dy1=((f(x+h)-f(x-h))/(h))-1/2*h;
dy2=(((-3*f(x))+4*f(x+h)-f(x+2*h))/(2*h))+1/3*h^2;
dy3=((f(x+h)-f(x-f))/2*h)-1/6*h^2;
  3 Comments
Adam
Adam on 23 Apr 2012
I do not know what I should do next, the result is some kind of strange
t=0.8;
h = 0:t:10^-5;
x=5;
f(x)=(x^2)+3;
dy=((f(x+h)-f(x-h))/(h))-1/2*h

Sign in to comment.

Answers (2)

Titus Edelhofer
Titus Edelhofer on 23 Apr 2012
Hi,
o.k., let's start with the h:
0:t:10^-5
will be the zero. Start with e.g.
h = 0.01;
Take a look at the chapter about defining functions (or search the doc for "function handles" on how to define f.
Titus

Walter Roberson
Walter Roberson on 23 Apr 2012
Algebra. What is f(x)=(x^2)+3 evaluated at (x+h) ? And at (x-h) ? And so on. Simplify and you get down to a nice formula.

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!