Equivalent Expression Of √10/√8: A Math Guide

by Andrew McMorgan 46 views

Hey math enthusiasts! Ever found yourself scratching your head over simplifying radical expressions? Well, you're not alone! Today, we're diving deep into a problem that might seem tricky at first glance but is totally conquerable with a few key steps. We're going to break down the expression 108\frac{\sqrt{10}}{\sqrt{8}} and figure out which of the given options is its equivalent. So, buckle up, and let's get started!

Understanding the Problem: 108\frac{\sqrt{10}}{\sqrt{8}}

When we first encounter an expression like 108\frac{\sqrt{10}}{\sqrt{8}}, it's tempting to just reach for a calculator, but where's the fun in that? Plus, on many math tests, you won't even have a calculator! The key here is to simplify radicals and manipulate the expression using mathematical rules. Our main goal is to get rid of the radicals in the denominator – a process called rationalizing the denominator. So, let's first break down why this is important and how we are going to tackle this problem.

First, why do we care about simplifying radical expressions? Well, in the world of mathematics, it's like tidying up your room. A simplified expression is much easier to work with, interpret, and compare with other expressions. It's all about clarity and efficiency. The expression 108\frac{\sqrt{10}}{\sqrt{8}} has radicals in both the numerator and the denominator, which, while not wrong, isn't the most simplified form. Our mission is to make it cleaner and easier to handle.

Next, let's talk about the strategy. As mentioned earlier, we aim to rationalize the denominator. This means we want to eliminate the square root from the bottom of the fraction. How do we do that? We'll use a clever trick: multiplying both the numerator and the denominator by the same radical that's in the denominator. In our case, that's 8\sqrt{8}. This works because multiplying a square root by itself gets rid of the radical (since aa=a\sqrt{a} \cdot \sqrt{a} = a). However, we've got to keep the fraction equivalent, so we multiply both the top and the bottom by the same thing. Think of it like multiplying by 1 – it changes the look but not the value. So, we are making good progress, guys! Keep up with the great work.

Step-by-Step Simplification

Okay, let's get our hands dirty and walk through the simplification process step-by-step. This is where the magic happens, and we transform our initial expression into something much more manageable. Remember, the goal is to make the math look easy peasy.

1. Rationalizing the Denominator

As we discussed, the first step is to rationalize the denominator of 108\frac{\sqrt{10}}{\sqrt{8}}. To do this, we'll multiply both the numerator and the denominator by 8\sqrt{8}:$\frac{\sqrt{10}}{\sqrt{8}} \cdot \frac{\sqrt{8}}{\sqrt{8}} = \frac{\sqrt{10} \cdot \sqrt{8}}{(\sqrt{8})^2}$ This might look a little intimidating, but don't worry! We're just following the plan we laid out. Multiplying the numerators gives us 108\sqrt{10} \cdot \sqrt{8}, and squaring the denominator, (8)2(\sqrt{8})^2, simply gives us 8. Remember, the square root and the square cancel each other out. This is a crucial step in simplifying radical expressions, and you'll see it come up time and time again in your math journey. Once you get the hang of this step, the rest of the problem becomes much smoother.

2. Simplifying the Numerator

Now let's focus on the numerator, which is 108\sqrt{10} \cdot \sqrt{8}. We can simplify this by using the property ab=ab\sqrt{a} \cdot \sqrt{b} = \sqrt{a \cdot b}. This property is super handy when dealing with radicals, so make sure you have it in your mental toolkit.

Applying this property, we get:$\sqrt{10} \cdot \sqrt{8} = \sqrt{10 \cdot 8} = \sqrt{80}$ Okay, we've combined the two radicals into one, but we're not done yet! The next step is to see if we can further simplify 80\sqrt{80}. This involves looking for perfect square factors within 80. Think of numbers like 4, 9, 16, 25, and so on – numbers that have whole number square roots. Can you spot any perfect squares that divide 80? You've got it! 16 is a perfect square (16=4\sqrt{16} = 4) and a factor of 80 (80 = 16 * 5). This is great news because it allows us to break down the radical into simpler terms. By identifying and extracting perfect square factors, we're making the radical smaller and easier to manage. This is a key technique in simplifying radicals, so let's see how it plays out in our problem.

3. Further Simplification of the Radical

We've got 80\sqrt{80}, and we know that 80 can be written as 16516 \cdot 5. So, we can rewrite our radical as:$\sqrt80} = \sqrt{16 \cdot 5}$ Now, we can use the property ab=ab\sqrt{a \cdot b} = \sqrt{a} \cdot \sqrt{b} in reverse to separate the radicals$\sqrt{16 \cdot 5 = \sqrt16} \cdot \sqrt{5}$ We know that 16=4\sqrt{16} = 4, so we can simplify further$\sqrt{16 \cdot \sqrt{5} = 4\sqrt{5}$ Awesome! We've simplified 80\sqrt{80} to 454\sqrt{5}. This is a much cleaner and simpler way to represent the radical. By breaking down the number under the radical and extracting perfect squares, we've transformed it into a more manageable form. Now, we're one step closer to our final answer. This is where the beauty of math shines – taking something complex and making it simple through systematic steps.

4. Putting It All Together

Now, let's put everything back together. Remember, we had:$\frac\sqrt{10} \cdot \sqrt{8}}{(\sqrt{8})^2}$ We simplified the numerator to 454\sqrt{5} and the denominator to 8. So, our expression now looks like this$\frac{4\sqrt{5}8}$ We're almost there! Now, we can simplify the fraction by dividing both the numerator and the denominator by their greatest common factor, which is 4$\frac{4\sqrt{5}{8} = \frac{4\sqrt{5} \div 4}{8 \div 4} = \frac{\sqrt{5}}{2}$ There it is! We've simplified the original expression 108\frac{\sqrt{10}}{\sqrt{8}} to 52\frac{\sqrt{5}}{2}. It might seem like a long journey, but each step was a logical progression towards simplification. We rationalized the denominator, simplified the radical in the numerator, and then reduced the fraction. By breaking the problem down into smaller, manageable steps, we were able to tackle it with confidence. Math is all about building skills and applying them step-by-step, and you guys are doing an amazing job!

Comparing with the Options

Alright, now that we've simplified 108\frac{\sqrt{10}}{\sqrt{8}} to 52\frac{\sqrt{5}}{2}, let's compare our result with the options provided. This is the final step in our journey, where we match our simplified expression with one of the given choices. It's like fitting the last piece of a puzzle – satisfying and rewarding!

Let's take a look at the options:

A. 2042\frac{\sqrt[4]{20}}{2} B. 1008\frac{100}{8} C. 255\frac{2 \sqrt{5}}{5} D. 20042\frac{\sqrt[4]{200}}{2}

Our simplified expression is 52\frac{\sqrt{5}}{2}. At first glance, none of the options might seem like an exact match, and this is where a little bit of mathematical intuition and pattern recognition comes into play. We need to see if we can manipulate any of these options to look like our simplified form. This often involves understanding the properties of radicals and exponents and being able to see different ways of expressing the same value. Math is not just about getting to an answer, but also about understanding how different forms can be equivalent. So, let's dive in and see if we can find our match!

Analyzing the Options

  • Option A: 2042\frac{\sqrt[4]{20}}{2}

    This option involves a fourth root, which is different from our square root. To compare it with our answer, we'd need to see if we can somehow rewrite it in terms of a square root. However, 20 doesn't have any obvious factors that are perfect fourth powers, making this option less likely. While it's not impossible that it's equivalent, it would require significant manipulation, and it's not immediately clear how to get there. So, we'll keep it in mind, but let's explore the other options before we circle back.

  • Option B: 1008\frac{100}{8}

    This option is a simple fraction with no radicals. If we simplify it, we get 252\frac{25}{2}, which is a rational number. Our simplified expression, 52\frac{\sqrt{5}}{2}, has a radical in it, so this option is definitely not equivalent. Sometimes, it's just as important to rule out the incorrect answers as it is to find the correct one. This helps narrow down the possibilities and can make the correct answer stand out more clearly. Option B is a good example of an answer that's clearly different from what we're looking for.

  • Option C: 255\frac{2 \sqrt{5}}{5}

    This option has a 5\sqrt{5} in it, which is promising! However, the coefficient and the denominator are different from our answer. To see if it's equivalent, we'd need to find a way to transform 255\frac{2 \sqrt{5}}{5} into 52\frac{\sqrt{5}}{2}, or vice versa. At first glance, there's no direct way to do this. We might try rationalizing the denominator or manipulating the fraction, but it doesn't seem to lead to our simplified form. So, while it looks similar, it's likely not the correct answer.

  • Option D: 20042\frac{\sqrt[4]{200}}{2}

    This option also involves a fourth root. Let's see if we can rewrite 2004\sqrt[4]{200} in a way that involves a square root. We can rewrite 200 as 1002100 \cdot 2, and since 100 is a perfect square, this might be a fruitful path. Let's explore this further!

Digging Deeper into Option D

Let's rewrite 2004\sqrt[4]{200} as 10024\sqrt[4]{100 \cdot 2}. Remember that the fourth root can be thought of as the square root of the square root:$\sqrt[4]200} = \sqrt{\sqrt{200}}$ Now, let's focus on 200\sqrt{200}. We can rewrite 200 as 1002100 \cdot 2, so$\sqrt{200 = \sqrt100 \cdot 2} = \sqrt{100} \cdot \sqrt{2} = 10\sqrt{2}$ Now, substitute this back into our expression$\sqrt{\sqrt{200} = \sqrt10\sqrt{2}}$ This doesn't seem to be getting us closer to 5\sqrt{5}. However, let's try another approach. Let's go back to 2004\sqrt[4]{200} and see if we can rewrite 200 in terms of its prime factors. 200 can be written as 23522^3 \cdot 5^2. So$\sqrt[4]{200 = \sqrt[4]2^3 \cdot 5^2}$ We can rewrite this as$\sqrt[4]{2^2 \cdot 2 \cdot 5^2 = \sqrt{\sqrt{2^2 \cdot 5^2 \cdot 2}} = \sqrt{2 \cdot 5 \sqrt{2}} = \sqrt{10 \sqrt{2}}$ Still not quite there, but let's stick with Option D a little longer. It feels like we're on the right track!

The Final Eureka Moment!

Okay, guys, let's rewind a bit and look at Option D with fresh eyes. We have 20042\frac{\sqrt[4]{200}}{2}. We've tried breaking down 200 into its factors, but let's try a different approach. Let's square the entire expression and see if that gets us anywhere. Squaring 20042\frac{\sqrt[4]{200}}{2} gives us:$\left(\frac\sqrt[4]{200}}{2}\right)^2 = \frac{(\sqrt[4]{200})2}{22} = \frac{\sqrt{200}}{4}$ Now we're talking! We know 200=102\sqrt{200} = 10\sqrt{2}, so$\frac{\sqrt{200}4} = \frac{10\sqrt{2}}{4} = \frac{5\sqrt{2}}{2}$ This still doesn't look like our simplified answer, but remember, we squared the expression! To get back to the original value, we need to take the square root$\sqrt{\frac{5\sqrt{2}{2}}$ This is getting complicated, and it doesn't seem to be leading us to 52\frac{\sqrt{5}}{2}. So, let's take a step back and reconsider our options. Sometimes, in math, you hit a dead end, and it's important to recognize that and try a different path. We've given Option D a good shot, but it's not panning out. Let's go back to the drawing board and see if we missed something.

Re-evaluating Our Strategy

We've explored each option pretty thoroughly, and none of them seem to directly match our simplified expression, 52\frac{\sqrt{5}}{2}. This might be a sign that we need to re-examine our simplification process or look for a clever trick we might have missed. Math problems sometimes have hidden complexities, and it's all about being persistent and creative in your approach.

Before we second-guess our simplification, let's just double-check our work. We rationalized the denominator, simplified the numerator, and reduced the fraction. Everything seems to be in order. So, let's think about what else we can do.

Sometimes, the key is to manipulate the answer choices themselves. We tried squaring Option D, but that didn't lead us anywhere. Let's go back to our simplified expression, 52\frac{\sqrt{5}}{2}, and see if we can manipulate it to look like one of the options. This might involve squaring it, cubing it, or multiplying it by a clever form of 1. The goal is to transform our answer into a form that matches one of the given choices.

Let's start by squaring our simplified expression:$\left(\frac\sqrt{5}}{2}\right)^2 = \frac{(\sqrt{5})2}{22} = \frac{5}{4}$ This doesn't match any of the options. But what if we try multiplying our simplified expression by 22\frac{\sqrt{2}}{\sqrt{2}} (which is just 1)? This might help us introduce a square root of 2, which appears in some of the options$\frac{\sqrt{5}{2} \cdot \frac{\sqrt{2}}{\sqrt{2}} = \frac{\sqrt{10}}{2\sqrt{2}}$ This still doesn't seem to match any of the options directly. We're hitting a bit of a wall here, guys! It's time to think outside the box.

The Aha Moment!

Okay, I think I see where we went wrong! We were so focused on simplifying 2004\sqrt[4]{200} that we might have missed a simpler approach. Let's go back to Option D, 20042\frac{\sqrt[4]{200}}{2}, and try rewriting it in a slightly different way.

We know that 200=1612.5200 = 16 \cdot 12.5. Wait a minute... 16 is 242^4! This could be the key! Let's rewrite 200 as 1612.5=2412.516 \cdot 12.5 = 2^4 \cdot 12.5. Now:$\sqrt[4]200} = \sqrt[4]{2^4 \cdot 12.5} = 2\sqrt[4]{12.5}$ This is interesting, but it's still not getting us directly to 5\sqrt{5}. However, let's think about what we're trying to achieve. We want to show that 20042\frac{\sqrt[4]{200}}{2} is equivalent to 52\frac{\sqrt{5}}{2}. So, let's set them equal to each other and see if we can prove it$\frac{\sqrt[4]{200}2} = \frac{\sqrt{5}}{2}$ If we multiply both sides by 2, we get$\sqrt[4]{200 = \sqrt5}$ Now, let's square both sides$(\sqrt[4]{200)^2 = (\sqrt5})^2$ This simplifies to$\sqrt{200 = 5$ Wait a second... this is not true! We know that 200=102\sqrt{200} = 10\sqrt{2}, which is definitely not equal to 5. So, Option D is not the correct answer.

Okay, this was a valuable exercise. We went down a rabbit hole, but we learned something important: sometimes, the most promising-looking path can lead to a dead end. It's crucial to be willing to re-evaluate your approach and look for other possibilities. We've ruled out Options B and D, and we've spent a lot of time on them. Let's go back to Options A and C and see if we can find a connection.

Back to Options A and C

Let's revisit Option A: 2042\frac{\sqrt[4]{20}}{2}. We haven't spent as much time on this one, so there might be something we missed. And let's also look at Option C: 255\frac{2 \sqrt{5}}{5} again, just to be sure.

We're looking for an expression that's equivalent to 52\frac{\sqrt{5}}{2}. Option C has a 5\sqrt{5} in it, but the fraction is 255\frac{2 \sqrt{5}}{5}. There's no obvious way to transform this into our simplified answer. So, let's focus on Option A.

Option A is 2042\frac{\sqrt[4]{20}}{2}. To compare this to our simplified answer, we need to get rid of the fourth root or somehow introduce a square root of 5. Let's try squaring both our simplified expression and Option A and see if we can find a connection:$\left(\frac\sqrt{5}}{2}\right)^2 = \frac{5}{4}$$\left(\frac{\sqrt[4]{20}}{2}\right)^2 = \frac{\sqrt{20}}{4}$ Now, let's simplify 20\sqrt{20}. We can rewrite 20 as 454 \cdot 5, so$\sqrt{20 = \sqrt4 \cdot 5} = \sqrt{4} \cdot \sqrt{5} = 2\sqrt{5}$ Substitute this back into our expression$\frac{\sqrt{20}4} = \frac{2\sqrt{5}}{4} = \frac{\sqrt{5}}{2}$ Wait a minute... this is the square root of our original simplified expression! So, we have$\left(\frac{\sqrt[4]{20}2}\right)^2 = \frac{\sqrt{5}}{2}$ Now, let's take the square root of both sides$\sqrt{\left(\frac{\sqrt[4]{20}{2}\right)^2} = \sqrt{\frac{\sqrt{5}}{2}}$ This doesn't seem to be getting us anywhere. We're going in circles again! It's time to take a deep breath and try a different approach.

The Final Solution!

Okay, guys, I think we've been overcomplicating things. Sometimes, the simplest solution is the best. Let's go back to Option A:$\frac\sqrt[4]{20}}{2}$ Instead of trying to manipulate this expression, let's try to manipulate our simplified expression, 52\frac{\sqrt{5}}{2}, to look like Option A. We need to introduce a fourth root somehow. How can we do that? Well, we can rewrite 5\sqrt{5} as 524\sqrt[4]{5^2}$\sqrt{5 = \sqrt[4]5^2} = \sqrt[4]{25}$ So, our simplified expression becomes$\frac{\sqrt{5}{2} = \frac{\sqrt[4]{25}}{2}$ Now, let's compare this to Option A, 2042\frac{\sqrt[4]{20}}{2}. They look very similar! The only difference is the number under the fourth root. We have 25 in our simplified expression and 20 in Option A. Could this be a mistake in the problem? Or are we still missing something?

Let's think... We've checked our simplification multiple times, and we're confident that 108\frac{\sqrt{10}}{\sqrt{8}} simplifies to 52\frac{\sqrt{5}}{2}. So, if there's an equivalent expression among the options, it should be 2542\frac{\sqrt[4]{25}}{2}.

However, none of the options exactly match 2542\frac{\sqrt[4]{25}}{2}. Option A is 2042\frac{\sqrt[4]{20}}{2}, which is close, but not quite the same. This is a tricky situation! It's possible that there's a typo in the problem, or that none of the options are actually equivalent to the original expression.

In a real-world test scenario, this is where you'd want to make an educated guess and move on. You've spent a good amount of time on this problem, and it's important to manage your time effectively. Based on our work, Option A is the closest to the correct answer, but it's not an exact match. So, if I had to choose, I'd go with Option A, but with a note that there might be an error in the problem.

Conclusion

Phew! That was quite a journey, guys! We tackled a challenging problem, explored different simplification techniques, and analyzed each answer choice in detail. We learned how to rationalize denominators, simplify radicals, and think critically about mathematical expressions. We also encountered a situation where the problem might have a typo, which is a valuable lesson in itself. Not every math problem has a perfect, clear-cut solution, and it's important to be able to think on your feet and make informed decisions.

Even though we didn't find an exact match among the options, we made significant progress in understanding the problem and applying our mathematical skills. Remember, math is not just about getting the right answer; it's about the process of learning, exploring, and problem-solving. And you guys did an amazing job today! Keep up the great work, and never stop questioning and exploring the wonderful world of mathematics!