Distinguish between removable and essential discontinuities. Decide, for the following functions whether the points of discontinuity are a) f(x, y) = xy/x + y b) c) f(x) = xx d) g(x) = x and = 2 e) h(x) = sin (1/x) f(x, y) = xy/x + y (x, y) = R - {(0, 0)} (x, y) = R - {(0, 0)} XER, x > 0 XER, X>0 X = R x = 0 XER, X < 0