Show transcribed image text MATH 2415 Lecture 14 06.pdf-Adobe Reader File Edit View Window Help 15756 | ▼ Tools Sign Comment Click on Sign to add text and place signatures on a PDF file. 14.6-Directional Derivatives and the Gradient Vector | 5 Practice Problems 1. Find the directional derivative of f(x, y)-at (1, 2) in the direction of the vector v-i +2 2. Find the directional derivative of f(x, y, z) =z.xy2 at (2, 1, 3) in the direction of the vector v=-i + 2j+2k. 3. The temperature at a point (x, y, z) is given by T(x, y, z)-200 e-rプ-22, where T is measured in °C and x, y, and z in meters. In which direction does the temperature increase most rapidly at P(2, -1, 2).? What is the maximum rate of increase in the temperature at this point? 4. Find the equation of the tangent plane to the surface xz +2x2y +y2 z3-11 at (2, 1, 1) 901 AM 10/16/2017