Why symsum does not provide the right result?

조회 수: 4(최근 30일)
Serbring
Serbring 2021년 5월 18일
댓글: Serbring 2021년 5월 18일
Hi all,
I need to find the symbolic solution of the sum of the mathematical series, but symsum does not provide the right result. Here you an example with the serie: .
syms i
symsum(i,i)
ans =
i^2/2 - i/2
This is very different from the theretical result. However, if I limit the series as follows:
symsum(i,i,0,100)
ans =
5050
That is corect. However, it is differente than
subs(symsum(i,i),i,100)
ans =
4950
Why symsum does not provide the right result?

채택된 답변

Jan
Jan 2021년 5월 18일
syms i n
symsum(i,i, 1, n)
ans = 
If you define the sum without limits like in symsum(i,i) something different is calculated according to the documentation ( doc symsum ):
F = symsum(f,k) returns the indefinite sum (antidifference) of the series f with respect to the summation index k. The f argument defines the series such that the indefinite sum F satisfies the relation F(k+1) - F(k) = f(k).
  댓글 수: 1
Serbring
Serbring 2021년 5월 18일
It worked. thank you so much.

댓글을 달려면 로그인하십시오.

추가 답변(0개)

제품


릴리스

R2020a

Community Treasure Hunt

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

Start Hunting!

Translated by