A photographer uses a light meter to measure the intensity of light from a flashbulb. the intensity for the flashbulb, I, measured in lux, is a function of the distance from the light, d, measured in metres, and can be represented by I(d)=10/d^2, d>0. a) determine the following, to two decimal places. i) the average rate of change in the intensity of light for the interval [1,3]. ii) the approximate instantaneous rate of change in the intensity of light at exactly 4 m from the flashbulb