Answer:
-0.017°c/km
Explanation:
for the contour provided , to estimate the value of directional derivative of this temperature function at Dubbo, New South Wales in the direction of sydney.
to also find the units,
it is posible to find the directional derivative for the temperature by calculating the rate of change of temperature on an average. This is found in between points at which a straight line can be drawn in between cities that crosess the zone temperature.
to find the direction of sydney, the change in temperature is from 30 to 24 degrees. from the scale that is there, the distance between the two cities are 350km
thus,
24 -30/350
= -0.017deg/km
therefore the required value is -0.017°c/km