An Efficiency Study of the Morning Shift at a Certain $f ( x ) = - x ^ { 3 } + 10 x ^ { 2 } - 3 x$

Short Answer

An efficiency study of the morning shift at a certain factory indicates that an average worker arriving on the job at 8:00 A.M. will have assembled $f ( x ) = - x ^ { 3 } + 10 x ^ { 2 } - 3 x$ transistor radios x hours later. Approximately how many radios will the worker assemble between 9:00 and 9:15 A.M.?