(Continiously) compound(ed) interest is e^(rate * time), e is not a rational number. Transcendental functions are commonly used in financial modelling, and once

(Continiously) compound(ed) interest is e^(rate * time), e is not a rational number. Transcendental functions are commonly used in financial modelling, and once they appear, nothing short of a full-blown CAS will give you 100% accurate results (not that you should care, because your model is off by more than floating point error).