Explain why the function is discontinuous at the given number a. (select all that apply.) f(x) = 1 x + 1 a = −1 lim x→−1 f(x) does not exist. f(−1) and lim x→−1 f(x) exist, but are not equal. lim x→−1+ f(x) and lim x→−1− f(x) exist, but are not equal. f(−1) is undefined. none of the above

Is there a direction u in which the rate of change of f(x, y)equals=x squared minus 3 xy plus 4 y squaredx2−3xy+4y2 at p(1,2) equals 14? give reasons for your answer. choose the correct answer below. a. no. the given rate of change is smaller than the minimum rate of change. b. no. the given rate of change is larger than the maximum rate of change. c. yes. the given rate of change is larger than the minimum rate of change and smaller than the maximum rate of change.