It's the same vector So, a lot of vectors we'll draw starting at the origin but we don't have to.
它们是同一个向量,通常我们都选原点作为向量的起点,但是我们不一定要这么做。
And, of course, I am not going to try to draw all these vectors in there.
当然,我无法画出所有的向量。
If the two level curves are tangent to each other that means they have the same tangent line. That means that the normal vectors should be parallel. Let me maybe draw a picture here.
如果两个等高线相切,说明它们的切线相同,也就是说他们的法向量应该平行,我再在这里画个图。
Most of the time, when we deal with vectors, we don't draw these arrows anymore.
多数情况下,当我们处理矢量时,就不再画出这些箭头了
Okay, so the rule for adding the two vectors is, you draw the first one and at the end of that first one, you begin the second one.
矢量的加法法则就是,先画出第一个矢量,然后在它的终点,再画第二个矢量
应用推荐