A person wants to sun bath for an hour. The intensity of the sun in the time interval [ 6 , 22 ] {\displaystyle {}[6,22]} (in hours) is given by the function
![{\displaystyle {}[6,22]}](https://wikimedia.org/api/rest_v1/media/math/render/svg/dc5f9564df4d74cc9bc4f63ba7eee79055b76139)
(in hours)
is given by the function
![{\displaystyle f\colon [6,22]\longrightarrow \mathbb {R} ,t\longmapsto f(t)=-t^{3}+27t^{2}-120t.}](https://wikimedia.org/api/rest_v1/media/math/render/svg/3dd5810786df2aac14ecf08383a81576563f6ef0)
