Consider the function as representing the value of an ounce of palladium in U$.$S$.$ dollars as a function of the time t in days.$$

R$($t$)=40$t $2$t$2$; t $=3$

Find the average rate of change of R$($t$)$ over the time intervals $[$t$,$ t $+$ h$],$ where t is as indicated and h $=1,0\mathrm{.}1,$ and $0\mathrm{.}01$ days. $($Use smaller values of h to check your estimates.$)$ HINT $[$See Example $1.]($Round your answers to two decimal places.$)$

h$10\mathrm{.}10\mathrm{.}01$Ave. rate

Estimate the instantaneous rate of change of R at time t$,$ specifying the units of measurement.

R$\text{'}(3)=---$Select$---$$$/$yr$$$$/$day$$$$/$oz$$$$/$item