Problem

Simplify (3k^3)/( square root of 18k)

The given problem is asking for the simplification of a mathematical expression that involves both polynomial and radical elements. You are required to simplify the fraction (3k^3) divided by the square root of (18k). To complete this, the rules of exponents, the properties of radicals, and algebraic manipulation are typically employed to simplify the expression into a form that no longer has a radical in the denominator, also known as rationalizing the denominator. This often involves factoring expressions, reducing any common factors between the numerator and the denominator, and applying the property that the square root of a product is equal to the product of the square roots when appropriate.

$\frac{3 k^{3}}{\sqrt{18 k}}$

Answer

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Solution:

Step 1: Simplify the square root in the denominator.

Step 1.1: Express $18k$ as a product of its prime factors.

$18k = 3^2 \cdot 2k$

Step 1.1.1: Extract the square factor from $18$.

$\frac{3k^3}{\sqrt{9 \cdot 2k}}$

Step 1.1.2: Represent $9$ as $3^2$.

$\frac{3k^3}{\sqrt{3^2 \cdot 2k}}$

Step 1.1.3: Enclose the terms under the radical in parentheses.

$\frac{3k^3}{\sqrt{3^2 \cdot (2k)}}$

Step 1.2: Extract the square root of the perfect square.

$\frac{3k^3}{3\sqrt{2k}}$

Step 2: Eliminate the common factor of $3$.

Step 2.1: Reduce the fraction by canceling out the common factor.

$\frac{\cancel{3}k^3}{\cancel{3}\sqrt{2k}}$

Step 2.2: Present the simplified expression.

$\frac{k^3}{\sqrt{2k}}$

Step 3: Rationalize the denominator by multiplying by the conjugate.

$\frac{k^3}{\sqrt{2k}} \cdot \frac{\sqrt{2k}}{\sqrt{2k}}$

Step 4: Simplify the expression in the denominator.

Step 4.1: Multiply the numerator and denominator by $\sqrt{2k}$.

$\frac{k^3\sqrt{2k}}{\sqrt{2k}\sqrt{2k}}$

Step 4.2: Raise the square root to the first power.

$\frac{k^3\sqrt{2k}}{(\sqrt{2k})^1\sqrt{2k}}$

Step 4.3: Repeat the exponentiation for clarity.

$\frac{k^3\sqrt{2k}}{(\sqrt{2k})^1(\sqrt{2k})^1}$

Step 4.4: Apply the exponent rule $a^m a^n = a^{m+n}$.

$\frac{k^3\sqrt{2k}}{(\sqrt{2k})^{1+1}}$

Step 4.5: Sum the exponents.

$\frac{k^3\sqrt{2k}}{(\sqrt{2k})^2}$

Step 4.6: Convert the square of the square root back to the original number.

$\frac{k^3\sqrt{2k}}{(2k)^1}$

Step 5: Cancel the common $k$ terms.

Step 5.1: Factor $k$ from $k^3\sqrt{2k}$.

$\frac{k(k^2\sqrt{2k})}{2k}$

Step 5.2: Reduce the fraction by canceling out the common $k$.

$\frac{\cancel{k}(k^2\sqrt{2k})}{\cancel{k}\cdot 2}$

Step 5.3: Present the final simplified expression.

$\frac{k^2\sqrt{2k}}{2}$

Knowledge Notes:

  1. Square Roots and Radicals: The square root of a number $a$ is a value that, when multiplied by itself, gives $a$. Radicals are symbols used to denote roots, such as $\sqrt{\cdot}$ for square roots.

  2. Prime Factorization: Breaking down a number into its prime factors helps simplify radical expressions.

  3. Rationalizing the Denominator: This process involves removing the radical from the denominator of a fraction by multiplying both the numerator and the denominator by an appropriate form of 1, such as $\frac{\sqrt{b}}{\sqrt{b}}$.

  4. Exponent Rules: The power rule states that $a^m \cdot a^n = a^{m+n}$. When raising a power to a power, you multiply the exponents, as in $(a^m)^n = a^{m \cdot n}$.

  5. Simplifying Expressions: This involves reducing fractions to their simplest form by canceling out common factors in the numerator and denominator.

  6. Algebraic Manipulation: The process of rearranging and simplifying algebraic expressions using various algebraic rules and properties.

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