This function applied to the sum of two operators can be computed with the Suzuki-Trotter decomposition. The equation “this function of X, times this function of Y, equals this function of Z” can be solved with iterated commutators of X and Y by the BCH formula. The transmission coefficient in the WKB approximation is expressed with this function where the argument is an integral of “the square root of V minus E.” The (*) wavefunction of the bound state of a delta function potential is expressed using two terms with this function, one with a positive and one with a negative argument. This function of “negative i times energy times time (10[1])over h-bar” is the factor for how wavefunctions evolve in time. Sinusoidal functions can be expressed by “complex” versions of, for 10 points, what inverse of the natural logarithm? ■END■