Let (in radians) be an acute angle in a right triangle and let and , respectively, be the lengths of the sides adjacent to and opposite. Suppose also that and vary with time. At a certain instant units and is increasing at unit/s, while and is decreasing at units/s. How fast is changing at that instant?.

It depends on the subject for me. some exams are easier than others so i usually go through it and answer questions i know based on my general knowledge, then double check after. going through the lesson can a lot  because the exams can be  very lesson-specific, but sometimes they are ridiculously long so a lot of people don't take the time. i did find that, when i went through the lessons, i was making 100's on my exams vs strictly using + the internet and  i make 90's. 

Ithink