Learn how to rationalize the denominator with a rational exponent

Brian McLogan2 minutes read

To simplify the expression \( \frac{2^{\sqrt{z}}}{\sqrt{z} - 1} \), the author advocates multiplying the numerator and denominator by the conjugate \( \sqrt{z} + 1 \), leading to a final simplified form of \( 2^{\sqrt{z}} \) when \( z \) is not equal to 1. This process involves transforming the denominator into \( z - 1 \) and applying the distributive property for clarity.

Insights

  • Multiplying both the numerator and denominator of the expression \( \frac{2^{\sqrt{z}}}{\sqrt{z} 1} \) by the conjugate \( \sqrt{z} + 1 \) effectively simplifies it, turning the numerator into \( 2^{\sqrt{z}}(\sqrt{z} + 1) \) and the denominator into \( z - 1 \), which is a crucial step in rationalizing the expression.
  • The final simplified expression, \( 2^{\sqrt{z}} \), is achieved by applying the distributive property and ensuring that \( z \) does not equal 1, thereby avoiding division by zero and presenting a clearer, more manageable form of the original expression.

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Recent questions

  • What is a mathematical expression?

    A mathematical expression is a combination of numbers, variables, and operators that represents a value or relationship. It can include constants, coefficients, and functions, and is used to convey mathematical ideas succinctly. Expressions can be simple, like \(2 + 3\), or complex, involving multiple operations and variables, such as \(3x^2 + 2y - 5\). They do not include an equality sign, which distinguishes them from equations. Understanding expressions is fundamental in mathematics, as they form the basis for equations and functions, allowing for the representation of various mathematical concepts.

  • How do you simplify an expression?

    Simplifying an expression involves reducing it to its most basic form while maintaining its value. This process typically includes combining like terms, eliminating unnecessary parentheses, and applying mathematical operations systematically. For example, in the expression \(3x + 2x - 5\), you would combine the like terms \(3x\) and \(2x\) to get \(5x - 5\). Additionally, simplification may involve factoring, distributing, or using properties of exponents and logarithms. The goal is to make the expression easier to work with, especially in solving equations or performing calculations.

  • What is a conjugate in mathematics?

    In mathematics, a conjugate refers to a pair of expressions that are identical in form but differ in the sign between them. For example, the conjugate of \(a + b\) is \(a - b\). Conjugates are particularly useful in simplifying expressions involving square roots or complex numbers. When multiplying a binomial by its conjugate, the result is a difference of squares, which eliminates the square root or imaginary part. This technique is often employed in rationalizing denominators or simplifying fractions, making it a valuable tool in algebra and calculus.

  • What does it mean to factor an expression?

    Factoring an expression means breaking it down into simpler components, or factors, that when multiplied together yield the original expression. This process is essential in algebra, as it allows for easier manipulation and solving of equations. For instance, the expression \(x^2 - 9\) can be factored into \((x - 3)(x + 3)\), which reveals its roots and simplifies further calculations. Factoring can involve techniques such as finding common factors, using the distributive property, or applying special formulas like the difference of squares or perfect square trinomials. Mastering factoring is crucial for solving polynomial equations and understanding their behavior.

  • What is the purpose of simplifying fractions?

    The purpose of simplifying fractions is to express them in their lowest terms, making them easier to understand and work with. A fraction is simplified by dividing both the numerator and the denominator by their greatest common divisor (GCD). For example, the fraction \(8/12\) can be simplified to \(2/3\) by dividing both the numerator and denominator by 4. Simplifying fractions is important in various mathematical operations, such as addition, subtraction, and comparison, as it helps to clarify the values being represented and ensures accuracy in calculations. It also aids in identifying equivalent fractions and understanding ratios.

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Summary

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Simplifying Expressions with Conjugates

  • To simplify the expression \( \frac{2^{\sqrt{z}}}{\sqrt{z} - 1} \), multiply both the numerator and denominator by the conjugate \( \sqrt{z} + 1 \). This results in the numerator becoming \( 2^{\sqrt{z}}(\sqrt{z} + 1) \) and the denominator transforming into \( (\sqrt{z})^2 - 1^2 \), which simplifies to \( z - 1 \).
  • After applying the distributive property and simplifying, the expression reduces to \( \frac{2^{\sqrt{z}}(\sqrt{z} + 1)}{z - 1} \). The final simplified form is \( \frac{2^{\sqrt{z}} + 2^{\sqrt{z}}}{1} \), which can be expressed as \( 2^{\sqrt{z}} \) when \( z \) is not equal to 1, ensuring that division by a rational exponent is avoided.
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