The most basic formula used in matching method is binomial complete square formula (A+B) = A+2AB+B. By using this formula flexibly, we can get various basic formula forms, such as: A+B = (A+B)-2AB = (A-B)+2AB; a+ab+b =(a+b)-ab=(a-b)+3ab= (a+b).
Method of completing a square
Matching method refers to transforming a formula (including rational formula and transcendental formula) or a part of a formula into a completely flat way or the sum of several completely flat ways through continuous deformation. This method is often used in identity deformation, and it is one of the powerful means to solve the problem by discovering the hidden conditions in the topic.
App application
1, factorization
Turning a polynomial into the product of several algebraic expressions in a range of values is called factorization of this polynomial, which is also called factorization of this polynomial.
Factorization is one of the most important identical deformations in middle school mathematics. It is widely used in elementary mathematics, and it is also widely used in finding roots and solving quadratic equations with one variable in mathematics. It is a powerful tool to solve many mathematical problems.
Factorization is flexible and ingenious. Learning these methods and skills is not only necessary to master the content of factorization, but also plays a very unique role in cultivating problem-solving skills and developing thinking ability. Learning it can not only review the four operations of algebraic expressions, but also lay a good foundation for learning scores; Learning it well can not only cultivate students' ability of observation, thinking development and calculation, but also improve students' ability of comprehensive analysis and problem solving.
2. Constant deformation
Identity deformation is a transformation of analytical expressions. Changing one algebraic expression into the same algebraic expression is called identity transformation or identity transformation. For example, replacing the algebraic expression 4x2y+3x2y with 7x2y is identity deformation.