convert expression containing symbolic variables into double array. apply 'subs' function first to substitute values for variables. in matlab

To convert an expression containing symbolic variables into a double array in Matlab, first, you need to substitute the values for the variables using the subs function. Then, you can use the eval function to evaluate the expression and obtain a numerical result.

Here is an example code that demonstrates this process:

main.m
syms x y; % define symbolic variables

expr = sin(x) + y; % define expression

% substitute values for variables
expr_sub = subs(expr, [x, y], [pi/2, 2]);

% evaluate the expression and obtain a double array
result = eval(expr_sub);
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In this example, we define two symbolic variables x and y, and an expression expr containing them. Then, we use the subs function to substitute the values pi/2 for x and 2 for y. Finally, we use the eval function to evaluate the expression expr_sub and obtain a double array result.