Find the average rate of change of the function over the given interval.. h(t) = cot t, intervals given [pi/4, (3pi)/4]. I've got it all laid out into the proper equation.. h(3pi/4)-h(pi/4)/(3pi/4 - pi/4). with. cot (3pi/4) - cot (pi/4) on the top (numerator). pi/2 on the bottom (denominator).