Simplify the Radical Expression: Fourth Root of 2 Divided by Fifth Root of 2

Question

Solve the following exercise:

2425= \frac{\sqrt[4]{2}}{\sqrt[5]{2}}=

Video Solution

Solution Steps

00:00 Simplify the following problem
00:03 Every number is to the power of 1
00:12 When we have a root of the order (B) on number (X) to the power of (A)
00:16 The result equals number (X) to the power of (A divided by B)
00:25 Apply this formula to our exercise
00:35 When we have division of powers (A\B) with equal bases
00:41 The result equals the common base to the power of the difference of the exponents (A - B)
00:44 Apply this formula to our exercise
00:53 Determine the common denominator and calculate the power
00:59 This is the solution

Step-by-Step Solution

Express the definition of root as a power:

an=a1n \sqrt[n]{a}=a^{\frac{1}{n}}

Apply this definition and proceed to convert the roots in the problem:

2425=214215 \frac{\sqrt[4]{2}}{\sqrt[5]{2}}= \frac{2^{\frac{1}{4}}}{2^{\frac{1}{5}}}

Below is the law of powers for division with identical bases:

aman=amn \frac{a^m}{a^n}=a^{m-n}

Let's apply this law to our problem:

214215=21415 \frac{2^{\frac{1}{4}}}{2^{\frac{1}{5}}}=2^{\frac{1}{4}-\frac{1}{5}}

In order to not overly complicate our calculations proceed to solve the expression in the power numerator from the last step separately and calculate the value of the fraction:

1415=514120=5420=120 \frac{1}{4}-\frac{1}{5}=\frac{5\cdot1-4\cdot1}{20}=\\ \frac{5-4}{20}=\frac{1}{20}

In the first step, we combined the two fractions into one fraction line, by expanding to the common denominator of 20 and performing the subtraction operation. (In the first fraction on the left we expanded both the numerator and denominator by 5, and in the second fraction we expanded both the numerator and denominator by 4) We then proceeded to simplify the resulting expression,

Returning once more to our problem, consider the result of the subtraction operation between the fractions that we just performed, as shown below:

21415=2120 2^{\frac{1}{4}-\frac{1}{5}}=2^{\frac{1}{20}}

Summarize the various steps of the solution:

2425=21415=2120 \frac{\sqrt[4]{2}}{\sqrt[5]{2}}=2^{\frac{1}{4}-\frac{1}{5}}=2^{\frac{1}{20}}

Therefore, the correct answer is answer C.

Answer

2120 2^{\frac{1}{20}}