Symbolic Toolbox Integration Error

Trialing the symbolic toolbox and attempting to run the 'Indefinite Integral of Univariate Expression' example from the int function documentation. Copy and pasting the exact code and recieve the following:

syms x
expr = -2*x/(1+x^2)^2;
F = int(expr)

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Error using sym/subsindex (line 855)

Invalid indexing or function definition. Indexing must follow MATLAB indexing. Function arguments must be symbolic variables, and function body must be sym expression.

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Is this a settings error? Demo/trial error? The symbolic differentiation tool works just fine. Many thanks for your help!

Answer 1

[madhan ravi]

You probably have a variable named int, clear that workspace using:

clear int
%or 
clear all

[Dan Lamone]

Thank you. Clear all did the trick. Cheers.