The derivation of differential formula assumes that the function y = f(x) is defined in a certain interval, and both x0 and x0+△x are in this interval. If the increment of the function Δ y = f (x0+△ x)? F(x0) can be expressed as Δ y = a Δ x+o (Δ x), where a is a constant independent of Δ x and o (Δ x) is an infinitesimal higher order of Δ x, then the function y = f o(δx) is differentiable at point x0.

The methods of learning calculus are:

1, preview before class

The old-fashioned topic is also inevitable in learning methods. It's an old saying, but I still want to mention it. Although everyone knows what to do, few people can really preview before class. Preview before class can let us know what we want to learn in advance, so as not to be at a loss in class, deepen our understanding during class, and thus quickly absorb new knowledge.

Step 2 take notes

Here mainly refers to the class notes, because the time of each class is limited, so the teacher will usually take the essence, so it is necessary to record it, which can deepen our understanding and facilitate our review and inspection in the later period.