(a+b)^3 Formula Proof

3 min read Jul 03, 2024
(a+b)^3 Formula Proof

The (a+b)^3 Formula Proof

The cube of a binomial expression (a+b) is a fundamental concept in algebra, and it has numerous applications in various branches of mathematics, physics, and engineering. In this article, we will delve into the proof of the (a+b)^3 formula, which is a crucial formula in algebra.

The Formula:

The formula for (a+b)^3 is:

(a+b)^3 = a^3 + 3a^2b + 3ab^2 + b^3

The Proof:

To prove this formula, we can use the principles of algebra and the distributive property of multiplication over addition.

Step 1:

Start with the expression (a+b)^3. We can rewrite this as:

(a+b)^3 = (a+b) × (a+b) × (a+b)

Step 2:

Expand each factor using the distributive property:

(a+b) × (a+b) = a^2 + 2ab + b^2

Now, multiply this expression with (a+b) again:

(a^2 + 2ab + b^2) × (a+b) = a^3 + 2a^2b + ab^2 + 2ab^2 + b^3

Step 3:

Collect like terms and combine them:

(a^3 + 2a^2b + ab^2) + (2ab^2 + b^3) = a^3 + 3a^2b + 3ab^2 + b^3

And there you have it! We have successfully derived the formula for (a+b)^3.

Applications and Importance:

The (a+b)^3 formula has numerous applications in algebra, geometry, trigonometry, and calculus. It is used to:

  • Expand binomial expressions and simplify equations
  • Find the volume of rectangular prisms and other geometric shapes
  • Calculate the area of triangles and other shapes
  • Solve problems involving right triangles and trigonometric identities
  • Model real-world phenomena, such as population growth and chemical reactions

In conclusion, the (a+b)^3 formula is a fundamental concept in algebra, and its proof is a testament to the power of algebraic manipulation and the distributive property.

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