I have no idea what you are actually doing, however converting between symbolic and double is straightforward (if inefficient in some contexts).
Example —
syms t
x = sym(42)
Il = 0;
Iu = 1;
intxt = int(x*t, Il, Iu)
fprintf('The integral of %.1f*t from %.1f to %.1f = %.2f\n', double(x), Il, Iu, double(intxt))
producing:
The integral of 42.0*t from 0.0 to 1.0 = 21.00
The online Run feature is still down for scheduled maintenance, so I cannot run that here.
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