Please Answer Questions 7 and 8.

7. Find the dimensions of a rectangle with perimeter 100 m whose area is as large as possible.at 8. Find the dimensions of a rectangle with area 1000 m whose perimeter is as small as possible. X. A model used for the yield Y of an agricultural crop as a func- tion of the nitrogen level N in the soil (measured in appropriate units) is KN 1 + N 2 where k is a positive constant. What nitrogen level gives the best yield? 10. The rate (in mg carbon/m / h) at which photosynthesis takes place for a species of phytoplankton is modeled by the function 100 1 P = where I is the light intensity (measured in thousands of foot- candles). For what light intensity is P a maximum