An approach could be: sqrt((2 * 2)!) = 4.90
Standard mathematical symbols (for this problem) are: addition, subtraction, multiplication, division, exponentiation, square root, factorization, parenthesis, positive, negative, ln, log. Superfactorials and such are not excluded, but not part of the desired solution. Any symbol having a value of its own, such as e, pi, and infinity, is not authorized.