Why does the RSUMS function from the Symbolic Math Toolbox return an incorrect result when I specify a range over which to integrate?

If I call the RSUMS function using the syntax:

syms x

rsums(x, 0, 10)

I receive a value of 5, which is incorrect. The value should be 50.

Answer 1

[MathWorks Support Team]

This bug has been fixed for Release 14 (R14). For previous releases, please read below for any possible workarounds:

This has been verified as a bug within the RSUMS function in the Symbolic Math Toolbox when called with an integration range. This bug has been fixed in the Symbolic Math Toolbox 3.1 (R14).

As a workaround, replace line 37 of the file :

$MATLAB\toolbox\symbolic\rsums.m

(where $MATLAB is your MATLAB root directory) with the following line:

r = (b-a)*sum(y)/n;

Then, execute the following command at the MATLAB prompt:

rehash toolboxcache