1. The profit function for a compnay is P(x)=-390+24x+5x^2-(1/3)x^3, where x represents the demand for the product(doghouse). Find the approximate change in profit for a 1-unit change in demand when the demand is at a level of 1000 doghouses. Use the differential. -my answer that i got is -$989976 am i correct? can profit be negative? 2. An oil slick is in the shape of a circle. Find the approximate increase in the area of the slick if tis radisu increases form 1.2 miles to 1.4miles. -my answer is 0.48pi miles^2 am i correct? and one more question, when would you use differentials and when would you use linear approximation? Thanks for your time.