EXAMPLE 1 Find the area enclosed by one loop of the four-leafed rose r = 3cos(20). SOLUTION The curve r = 3cos(20) is sketched in the figure to the left. Notice from the figure that the region enclosed by the right loop is swept out by a ray that rotates from 8 = -7/4 to 0 = 7t/4. Therefore Formula 4 gives A = de de Video Example de Tutorial Online Textbook (1+005 (40 )) de NI