Maximum Value Identification: Comparing Numerical Options

Question

Choose the largest value

Video Solution

Solution Steps

00:00 Choose the largest value
00:03 Let's look at the numbers themselves, and the largest one
00:12 The root of a number larger than another number is also larger than its root
00:17 Therefore this is the largest expression
00:20 And this is the solution to the question

Step-by-Step Solution

To determine which of the suggested options has the largest numerical value, we will use the definition of root as a power:

an=a1n \sqrt[n]{a}=a^{\frac{1}{n}} Let's substitute each one of the square roots in the suggested options with powers:

2212331244125512 \sqrt{2}\rightarrow2^{\frac{1}{2}}\\ \sqrt{3}\rightarrow3^{\frac{1}{2}}\\ \sqrt{4}\rightarrow4^{\frac{1}{2}}\\ \sqrt{5}\rightarrow5^{\frac{1}{2}}\\ Now let's note that all the expressions we got have the same exponent (and their bases are positive, we'll also mention, although it's obvious), therefore we can determine the trend between them using only the trend between their bases, since it's identical to it:

5>4>3>2\hspace{4pt} (>0)\\ \downarrow\\ 5^{\frac{1}{2}}>4^{\frac{1}{2}} >3^{\frac{1}{2}}>2^{\frac{1}{2}} In other words, we got that:

\sqrt{5}>\sqrt{4}>\sqrt{3}>\sqrt{2} Therefore the correct answer is answer D.

Answer

5 \sqrt{5}