Dr. Silas studies a culture of bacteria under a microscope. The function b_1 (t) = 1200 (1.8)^t t b t = represents the number of bacteria t hours after Dr. Silas begins her study. (a) What does the value 1200 represent in this situation? (b) What does the value 1.8 represent in this situation? (c) The number of bacteria in a second study is modeled by the function b_2 (t) =1000 (1.8)^t What does the value of 1000 represent in this situation? What does the difference of 1200 and 1000 mean between the two studies?

For every corresponding pair of cross sections, the area of the cross section of a sphere with radius r is equal to the area of the cross section of a cylinder with radius and height 2r minus the volume of two cones, each with a radius and height of r. a cross section of the sphere is and a cross section of the cylinder minus the cones, taken parallel to the base of cylinder, is the volume of the cylinder with radius r and height 2r is and the volume of each cone with radius r and height r is 1/3 pie r^3. so the volume of the cylinder minus the two cones is therefore, the volume of the cylinder is 4/3pie r^3 by cavalieri's principle. (fill in options are: r/2- r- 2r- an annulus- a circle -1/3pier^3- 2/3pier^3- 4/3pier^3- 5/3pier^3- 2pier^3- 4pier^3)