Suppose that the revenue $($in dollars$)$ from the sale of a product is given by

R $=40$x $+0\mathrm{.}8$x$20\mathrm{.}001$x$3,$

where x is the number of units sold.

Find each indicated derivative.

R$\text{'}$

$=$

R$\text{'}\text{'}$

$=$

How fast is the marginal revenue

MR

changing when

x $=10?$