When a bactericide is added to a nutrient broth in which bacteria are growing, the bacterium population continues to grow for a while, The growth rate at t=0 hours is | bacteria per hour. but then stops growing and begins to decline. The size of the population at time t (hours) is b - 8' + 8 1-8 { Find the growth rates at 1 = 0 hours, 1= 4 hours, and t = 8 hours. The growth rate at t = 4 hours is |bacteria per hour. The growth rate at t =8 hours is bacteria per hour