Dear tutors, please help me with a quiz. I have 50mins. It is 5:05 PM in my country (CA), so please put your work until 5:55. Please be on time and don't put any explanation. And it is fine if you didn't finish it. Please don't quit in the middle. Please just upload your work and share it with me! If you do so, I will thumbs up to you even you didn't finish it. Also, please highlight your answer. Appreciate,

Here is my question:

Given the function f (:13, y) = cos10392) A. Find fzy = % (g). {10 points} B. Find an expression for the total differential df. (5 points} C. If :1: changes from 1.1 to 1 and 3; changes from 0.4 to 0.5, use the total differential to approximate the change in the function f . i.e. Af m? (5 points} 1 VII11.2 l Hint: %(cos_1u) = In]