Let f be a real-valued function of two variables (x, y) that is defined on the square q = {(x, y) i 0 ~ x ~ i, 0 ~ y ~ i} and is a measurable function of x for each fixed value of y. for each (x, y) e q let the partial derivative a f / ay exist. suppose there is a function g that is integrable over [0, 1] and such that i~~(x, y)1 ~g(x)forall(x, y)eq. prove that