you can compute e(-t) via power series too, adding seconds to seconds squared and seconds cubed The argument of exp does have to be dimensionless, exactly beca

you can compute e(-t) via power series too, adding seconds to seconds squared and seconds cubed The argument of exp does have to be dimensionless, exactly because adding seconds to seconds squared doesn't work. If t has units of time, there has to be another factor with units of inverse time, for example continuous compound interest is exp(rate*time).