I keep getting stuck, any help is much appreciated!
Question:
A rectangle initially has the dimensions 2cm by 4cm. All sides begin increasing in length at a rate of 1cm/s. At what rate is the area of the rectangle increasing after 20 s.
so area would be (4+t)(2+t) and after multiplying that I get t^2+6t+8. When I differentiate, that gives me the rate, correct? Which would be 2t+6 and when t=20s, the rate would be 46cm/s?
Looks good. When , the area is , and when , the area is , an increase of , and when , the area is , an increase of , which suggests that when , the rate of increase is cm/s.