Question

Express in exponential form. $$4 \sqrt[3]{x y}$$

Short answer

The expression in exponential form is \(4x^{1/3}y^{1/3}\).

Step-by-step solution

Understanding the Expression

To express the given expression, \(4 \sqrt[3]{x y}\), in exponential form, recognize that the cube root is the same as raising a number to the power of 1/3.

Expressing the Cube Root in Exponential Form

Since the cube root is equivalent to the power of 1/3, rewrite the expression as \(4(x y)^{1/3}\).

Applying the Exponent to Both x and y

Apply the exponent to both the variables inside the parentheses. The final exponential form is \(4x^{1/3}y^{1/3}\).

Key concepts

Cube Root

When solving mathematical problems, understanding the concept of a cube root is crucial. The cube root of a number, represented as \( \sqrt[3]{n} \) , is a value that, when multiplied by itself three times, gives the original number \( n \) . It's like asking, 'What number can I multiply by itself twice to get \( n \) ?'

In simpler terms, if \( x^3 = n \) , then \( x \) is the cube root of \( n \) , and we write \( x = \sqrt[3]{n} \) . Now, translating cube roots into exponential form utilizes the fact that a cube root is the same as raising to the power of one-third, hence \( \sqrt[3]{n} = n^{1/3} \) . This knowledge is crucial for converting expressions with cube roots into a more workable exponential form which is often required for algebraic manipulations, calculus, and other higher-level math.

Exponents

Exponents represent how many times a number, known as the base, is multiplied by itself. The exponent is written as a superscript to the right of the base. For instance, \( 5^3 \) means you multiply 5 by itself three times (5 * 5 * 5).

Exponents can also be fractions, which often describe roots. As seen in the cube root example, the expression \( n^{1/3} \) represents the cube root of \( n \) . A crucial aspect of dealing with exponents is understanding how to apply them to multiple factors, such as \( (xy)^{1/3} \) , which indicates that both \( x \) and \( y \) should be raised to the power of one-third. This rule simplifies the process of raising entire expressions to a power and allows for the straightforward conversion into exponential form.

Radicals

Radicals are another way to represent roots. The most familiar radical is the square root, but radicals can represent any root, such as the cube root, fourth root, and so on. A radical consists of a radical symbol (\( \sqrt{} \) ) and a radicand—the number inside the radical.

When working with radicals, particularly when converting them into exponential form, the index of the radical—which dictates the root—is essential. If no index is specified, it's assumed to be a square root (index of 2). In the case of \( \sqrt[3]{x y} \) , the index is 3, indicating a cube root. The expression under the radical can often be simplified by recognizing that \( \sqrt[n]{a^m} = a^{m/n} \) , which is why we can express \( \sqrt[3]{x y} \) as \( x^{1/3} y^{1/3} \) . Teaching students to convert between radicals and exponents not only enhances their algebraic skillset but also deepens their understanding of the underlying mathematical relationships.