描述同一物理过程或者状态的两个相关物理量的量值之间的关系,不仅可以用数学表达式来表示,也可以用图象来表示.借助于图象不仅可以直观明了地看出两者的量值间的对应关系,而且往往还可以利用图象上的内含特征,如图线的斜率、图线在坐标轴上的截距、图线与坐标轴所夹区域的面积 The relationship between the magnitudes of two related physical quantities describing the same physical process or state can be expressed not only by mathematical expressions but also by images. Not only can the images be intuitively and clearly understood by the use of images. Correspondences between magnitudes, and often also the use of embedded features on the image, such as the slope of the graph line, the intercept of the graph line on the axis, the area of ​​the area between the plot and the axis