微積分本質(zhì)——導數(shù)的悖論

S-t圖像

v-t圖像

速度需要時間點的對比

velocity：the distance travelled per unit time

dt : the difference in time

the resulting change in the height of the graph

ds: the resulting difference in distance

the velocity at some point in time: ds/dt(t)

dt的值無限接近于0

ds/dt=the slope of a line tangent to the graph at a single point

dt is not "infinitely small", not 0

dt非常接近0