A start-up sells a seasonal gadget. Its monthly revenue (in thousands of dollars) since launch is modeled by
$R(t) = -0.4 t^3 + 8 t^2 + 40 t + 180, \quad t \geq 0.$
Here $t$ is the number of months since launch. (Round to 1 decimal place as needed.)
AFind the interval of time where $R$ is concave up (use interval notation).
BFind the interval of time where $R$ is concave down.
CFind any inflection point(s): $t =$
$R(t) = -0.4 t^3 + 8 t^2 + 40 t + 180, \quad t \geq 0.$
Here $t$ is the number of months since launch. (Round to 1 decimal place as needed.)
AFind the interval of time where $R$ is concave up (use interval notation).
BFind the interval of time where $R$ is concave down.
CFind any inflection point(s): $t =$