6. [0/1 Points] DETAILS PREVIOUS ANSWERS LARCALCET7 13.4.014. Consider the following. (Round your answers to four decimal places.) f( x, y) = x cos(y) (a) Find f(9, 4) and f(9.1, 4.05) and calculate Az. f(9, 4) = 8.9780 X f(9.1, 4.05) = 9.07727 X Az = 0.1 X (b) Use the total differential dz to approximate Az. dz = Need Help? Read It Watch It 7. [-/1 Points] DETAILS LARCALCET7 13.4.015.MI. Find z = f(x, y) and use the total differential to approximate the quantity. (Round your answer to two decimal places). (2.04)2(8.98) - 22(9) Need Help? Read It Master It