Consider a rectangle of length l inches and width w inches. find a formula for the perimeter of the rectangle. use upper case letters. p = l+l+w+w (b) if the length and width of the rectangle are changing with respect to time, find dp dt . use dl dt and dw dt and not l ' and w ' . dp dt = 2( dl dt)+2( dw dt) (c) suppose the length is increasing at 2 inches per hour and the width is decreasing at 3 inches per hour. how fast is the perimeter of the rectangle changing when the length is 40 inches and the width is 104 inches?