\frac{e^{\varepsilon q(d,r)}\mu(r)}{\int e^{\varepsilon q(d,r)} \mu(r) \, dr}.\,\! .
Now, if a single change in d\,\! changes q\,\! by at most \Delta q\,\! then the numerator can change at most by a factor of e^{\varepsilon\Delta q}\,\! and the denominator minimum by a factor of e^{-\varepsilon\Delta q}\,\!.