MATLAB: The order of free symbolic variables

symbolic variables

Hello!I have a question about the order of free symbolic variables.

==========

syms X Y
f=sin(X+Y);
symvar(f,1)
ans =
X

==========

Since abs('Y'-'x')<abs('X'-'x'), why the free symbolic variable of 'f' is not'Y'?

Thanks a lot.

Best Answer

https://www.mathworks.com/help/symbolic/symvar.html

Under Algorithms:

When sorting the symbolic variables by their proximity to x, symvar uses this algorithm:

The variables are sorted by the first letter in their names. The ordering is x y w z v u ... a X Y W Z V U ... A. The name of a symbolic variable cannot begin with a number.

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MATLAB: How to calculate gradients of a symbolic function

%construct the input
syms x y z
f(x,y,z) = 2*y*z*sin(x) + 3*x*sin(z)*cos(y);
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MATLAB: How to express a symbolic variable in function of other symbolic variables,

With newer MATLAB versions, you can use

syms f(y,z)
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Best Answer

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