To test an individual s use of a certain mineral a researcher injects a small amount of a radioactive form of that mineral into the person s bloodstream The mineral remaining in the bloodstream is measured each day for several days Suppose the amount of the mineral remaining in the bloodstream in milligrams per cubic centimeter t days after the initial injection is approximated by C t 2t 3 1 2 Find the rate of change of the mineral level with respect to time for 7 5 days The rate of change of the mineral level with respect to time for 7 5 days is approximately Round to two decimal places as needed milligrams per cubic centimeter per day