Solving a taylor serie with matlab. Homework question
1 view (last 30 days)
Show older comments
Oskar Nordström
on 3 Dec 2020
Answered: Alan Stevens
on 3 Dec 2020
Taylor serie of ln x:
ln x = (x − 1) − ((x − 1)^2)/ 2 + ((x − 1)^3)/ 3 − . . .
I need to find an approximately value of ln 3. The question suggested that we should replace x with 1/3 and then take the sum of all terms with absolute value bigger than 1e-8.
The questions suggested solution:
tol=1e-8; s=0; i=0;
term=;
while abs(term) > tol
s=s+term;
i=i+1;
term=...;
end
disp(-s)
What i've tried
tol=1e-8; s=0; i=1;
term = -2./3;
while abs(term) > tol
s = s + term;
i=i+1;
term = ((-2./3).^i)./i;
end
disp(-s)
My code gives the answear 0.51. The answear to ln 3 is 1.098...
How do i solve this?
0 Comments
Accepted Answer
Alan Stevens
on 3 Dec 2020
There's a multiplier of (-1)^(i-1) that you need. Try
tol=1e-8; s=0; i=1;
k = -2/3;
s = k;
err = 1;
while err > tol
sold = s;
i=i+1;
term = (-1)^(i-1)*(k.^i)./i;
s = sold + term;
err = abs(s-sold);
end
disp(-s)
0 Comments
More Answers (0)
See Also
Categories
Find more on Signal Analysis in Help Center and File Exchange
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!