摘要
It is easy to find the area of a rectangle or a triangle,even a polygon,which it is found by dividing it into triangles then summing the areas of the triangles.How to find the area of the region R that is bounded
It is easy to find the area of a rectangle or a triangle, even a polygon, which it is found by dividing it into triangles then summing the areas of the triangles. How to find the area of the region R that is bounded below by the x --axis and above by the curves of f（x） is not easy work because of the regions without straight sides. However, the fundamental theorem of calculus（part 2） is showed us how to find the area under a curve, which it is the graph of the function
