Avalanche forecasters measure the temperature gradient startfraction dt over dh endfraction , which is the rate at which the temperature in a snowpack t changes with respect to its depth h. a large temperature gradient may lead to a weak layer in the snowpack. when these weak layers collapse, avalanches occur. avalanche forecasters use the rule of thumb that if startfraction dt over dh endfraction exceeds 10 degrees upper c divided by m anywhere in the snowpack, conditions are favorable for weak-layer formation, and the risk of avalanche increases. assume the temperature function is continuous and differentiable. complete parts (a) through (d) below. a. an avalanche forecaster digs a snow pit and takes two temperature measurements. at the surface (hequals0), the temperature is negative 12 degrees upper c. at a depth of 1.7 m, the temperature is negative 3 degrees upper c. using the mean value theorem, what can he conclude about the temperature gradient?