Remember, partial f, partial x was obtained by y That means I am slicing the graph of f by a plane that is parallel to the x, z plane.
要记得，在这里的fx中,是作为常量保持不变的。，looking，at，the，situation，where，y，is，held，constant。,这是我用一个平行于xz坐标系的平面,横截了f，所得到的图形。
z I do F dot n. That just gives me the z component which might involve x, y and z.
把F和n做内积，于是得到,它由x，y，z组成。
So, let's do our first example. Let's say I give you a function f = -y because it doesn't depend on x.
让我们举出第一个例子，给出一个函数,它看上去有点奇怪，f，=，-y。，OK，，so，it，looks，a，little，bit，silly,因为它跟x无关。
The power of linearity is F=k1+k2 if I come across f of x, y, z equals k1 plus k2, if it is a linear equation, I don't have to go and solve it all over again.
线性的威力是,一个方程，如果它是个线性方程，那么我就不用再去解他了。
The power of linearity is F=k1+k2 if I come across f of x, y, z equals k1 plus k2, if it is a linear equation, I don't have to go and solve it all over again.
线性的威力是,一个方程，如果它是个线性方程，那么我就不用再去解他了。
应用推荐