Find the equation of the tangent line to the graph of f at the given point. 3. /(x) = = T - 4 Solve the following related rate problem. Express the result as an exact value. 9. A funnel at an oil refinery is in the shape of an inverted cone with a diameter of 12 m and a depth of 8m. Oil is flowing out of the funnel at a rate of 54m/h. At what rate is the height of the oil changing the instant the oil in the funnel is 6m deep? (10 pts)