expt

(expt z1 z2)

Returns z1 raised to the power z2. An exact base with an exact integer exponent gives an exact result, including a ratio for a negative exponent; (expt 0 0) is 1. A non-integer exponent gives a flonum, even when the root is exact: (expt 4 1/2) is 2.0. There are no complex results.