A cylindrical tank has a feed stream, qf, and an effluent stream, qe. A controller on the FEED stream is used (not the effluent stream). The effluent flow is at a CONSTANT volumetric flow rate of qe= l . The feed flow is used to control the height, qf = q* - k (h - h*), where l q* The constant density is given by r. The tank has an area A. a. (8 points) Show the balance equation to get dh(t)/dt