Les Identités Remarquables
This page introduces the concept of identités remarquables (remarkable identities) in mathematics, focusing on three key formulas and their applications. These formulas are crucial for algebraic manipulations and problem-solving in mathematics.
The three main identités remarquables presented are:
- (a+b)² = a² + 2ab + b²
- (a-b)² = a² - 2ab + b²
- (a+b)(a-b) = a² - b²
Definition: Identités remarquables are algebraic formulas that express the expansion of certain squared binomials and the product of the sum and difference of two terms.
The document provides several examples to illustrate the application of these formulas:
Example: (x + 1)² = x² + 2x + 1
This example demonstrates the expansion of (a+b)² where a = x and b = 1.
Example: (h-x)² = h² - 2hx + x²
This shows the application of the (a-b)² formula.
Example: (x+5)(x-5) = x² - 5² = x² - 25
This example illustrates the use of the (a+b)(a-b) formula.
The page also covers distributivity rules:
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Simple distributivity:
- k(a+b) = ka + kb
- k(a-b) = ka - kb
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Double distributivity:
- (a + b)(c + d) = ac + ad + bc + bd
Highlight: Understanding and mastering these identités remarquables and distributivity rules is crucial for simplifying complex algebraic expressions and solving equations efficiently.
These formulas are particularly important for students studying algebra, especially those in 3ème (9th grade in the French education system), as they form the foundation for more advanced mathematical concepts.