LetRbe the reaction of the body to some stimulus of strengths(measured in the appropriate units). The sensitivitySis defined to be the rate of change of the reaction with repect tos. Suppose that, for the particularRands, the following experimental formula has been used:

R=（20+28s^0.9）/(1+9s^0.9)

The sensitivitySat equals _____ (units of )/(units of )

how can I find the unit of the sensitivity

I get s=64.08 but I don't know how to defined the unit