In each of Problems 1 through 8, determine whether F is conservative in the given region D. If it is, find a potential function. If D is not defined, it is understood to be the entire plane. 1. F= y³i+ (3xy² - 4)j 2. F = (6y+yey)i + (6x + xe*)j 3. F = 16xi +(2- y²)j 2015 lepingi 4. F= 2xy cos(x²)i+sin(x²)j