Question 3 25 pts If the total differential of a function is zero, then the function is constant. O True O False Question 4 25 pts The total differential of a function f(@, y) approximates how much the function changes due to small changes of * and y. O True FalseCalculate the total differential of z=o'y try' -5x2 - 3xy + 4y' -10x -14y -30. O (2x + 2y - 3) dz O (x2 + 2xy - 3x + 8y - 14) dx + (2xy + y' -10x - 3y - 10) dy O (-2x - 2y + 3) dz O (2ary +y' - 10x - 3y - 10) dax + (x2 + 2xy - 3x + 8y - 14) dy Question 2 25 pts Estimate the value of v954.81 + 1528.81 by using differentials with regard to the function f(x, y) = Vx ty. Hint: 954.81 = (30 + 0.9) and 1528.81 = (40 - 0.9)2. O 49.82 O 49.84 49.81 O 49.83