3. The wind-chill index W is the perceived temperature when the actual temperature is T and the wind speed is v, so we can write W = f(T, v). The following table of values is an excerpt from Table 1 in Section 14.1. Wind speed (km/h) U 20 T 30 40 50 60 70 - 10 - 18 - 20 - 21 - 22 - 23 -23 Actual temperature ('C) - 15 -24 26 - 27 -29 -30 -30 - 20 -30 -33 -34 - 35 -36 -37 - 25 -37 - 39 -41 -42 -43 -44 (a) Estimate the values of fr(-15, 30) and f.(-15, 30). What are the practical interpretations of these values