54. Operations with radicals

Página 54

Operations with radicals are one of the fundamental topics in mathematics that are frequently addressed in Enem exams. Radicals are mathematical expressions involving the root operation. Understanding how to manipulate and operate with these radicals is crucial for solving a variety of mathematical problems.

First, it is important to understand what a radical is. A radical is an expression of the form n√a, where n is the index of the radical and a is the radicand. The index indicates which root we are considering (eg square root, cube root, etc.), while the radicand is the number or expression under the radical.

Basic operations with radicals include addition, subtraction, multiplication, and division. To add or subtract radicals, they must be "similar", which means they must have the same index and the same radicand. For example, √3 + 2√3 = 3√3. Note that this is similar to adding algebraic variables, like x + 2x = 3x.

Radical multiplication and division are a bit more complex, but follow similar rules. To multiply radicals, you multiply the radicands and keep the index the same. For example, √2 * √3 = √6. To divide radicals, you divide the radicands and keep the same index. For example, √8 / √2 = √4 = 2.

In addition, there are some important properties of radicals that can be useful for simplifying expressions. The first is the product property: n√(ab) = n√a * n√b. This means that the root of a product is equal to the product of the roots. The second is the quotient property: n√(a/b) = n√a / n√b. This means that the root of a quotient is equal to the quotient of the roots.

Also, there are rules for dealing with powers under a radical. If you have a number raised to a power under a radical, you can move the power outside the radical by multiplying it by the index. For example, √(a^2) = a. This is known as the radical power property.

Finally, it's important to understand how to rationalize the denominator when you have a radical in the denominator of a fraction. This is done by multiplying the numerator and denominator by the conjugate of the denominator. The conjugate of a number is the number with the sign of the radical term reversed. For example, the conjugate of a + √b is a - √b.

In summary, operations with radicals are a crucial part of mathematics that are often tested on the ENEM. Understanding how to add, subtract, multiply and divide radicals, as well as how to simplify expressions with radicals, can significantly help in solving mathematical problems.

It is important to practice these skills regularly, as familiarity with radical operations is essential for effective problem solving. With time and practice, operating with radicals will become second nature, allowing you to focus on understanding and solving the problem at hand rather than struggling with the underlying math.

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5555. Composite functions