The function sym converts numbers into exact expressions, while the function double does the reverse. Exemplary results of both expressions are given in Table 3.2.
Table 3.2:
Converting numerical or symbolic expressions
Matlab
Result
sym(sqrt(2))
sqrt(2)
sym(2.3654)
11827/5000
double(sin(2)+log(3))
2.0079
You can get an idea of the magnitude of an exact expression by using the command double.