1. Square difference formula: a? -B? =(a+b)(a-b)；
2. Arc length calculation: l = nπ r/180;
3. Complete cubic summation formula: (a? +b？ )=a？ +3a？ b+3ab？ +b？ ;
4. Triangle height = area × 2 bottom;
5. Trigonometric inequality: | a |≤ b
Knowledge expansion:
Mathematical formula is an expression method that people find some connection between things in nature and express it in some way.
It represents the equal or unequal relationship between the quantities of different things in nature, accurately reflects the internal and external relations of things, and is the basis for us to reach another thing from one thing, so as to better understand the essence and connotation of things.
According to the semantic inference rules of predicate logic, semantics should be consistent, that is, for a propositional logic statement set F, if and only if there is an explanation that at least all elements of F are true under I, then F is semantically consistent.
In propositional logic semantics, an assignment cannot give a propositional atomic formula both truth and false. In propositional logic semantics, under the same interpretation, a set cannot belong to both the extension of a predicate and the extension of this predicate.
Claiming to be scientific, but vague, lacking specific weights and measures. Action definitions (for example, public variables, objects that belong to or can be checked by outsiders) cannot be used.
The principle of simplicity cannot be satisfied, that is, when many variables appear, the answer cannot be obtained in the simplest way. Use ambiguous language and a lot of technical terms to make the article look scientific.
Lack of boundary conditions, rigorous scientific theory clearly defines the limited scope, and clearly points out when and where the prediction phenomenon is applicable and when and where it is not applicable.
Mathematical formula is an important part of mathematical knowledge. With the mastery of mathematical formulas, students can use mathematical knowledge more skillfully to solve practical problems.