Chapter 7: Problem 110
Write in the form \(a+b i\). $$ \frac{4-\sqrt{-8}}{2} $$
Short Answer
Expert verified
The expression is \(2 - \sqrt{2}i\).
Step by step solution
01
Simplify the expression
Notice that the expression is given as \( \frac{4-\sqrt{-8}}{2} \). The term \( \sqrt{-8} \) needs to be converted to include the imaginary unit \( i \). Rewrite \( \sqrt{-8} \) as \( \sqrt{8} \cdot i \). Since \( \sqrt{8} = 2\sqrt{2} \), this becomes \( 2\sqrt{2}i \). Therefore, the expression is \( \frac{4 - 2\sqrt{2}i}{2} \).
02
Divide each term by 2
Now separate the expression \( \frac{4 - 2\sqrt{2}i}{2} \) into two fractions: \( \frac{4}{2} - \frac{2\sqrt{2}i}{2} \). Simplify each fraction individually by dividing both the real and imaginary parts by 2.
03
Simplify each term
Simplify \( \frac{4}{2} \) to 2, and \( \frac{2\sqrt{2}i}{2} \) to \( \sqrt{2}i \). Therefore, the expression becomes \( 2 - \sqrt{2}i \).
04
Express in the form \(a + bi\)
The expression after simplification is \(2 - \sqrt{2}i \), which is already in the form \(a + bi\) where \(a = 2\) and \(b = -\sqrt{2}\).
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Imaginary Unit
The imaginary unit, denoted as \( i \), is a crucial concept in the realm of complex numbers. It is defined by the property \( i^2 = -1 \). This may seem peculiar because it allows for the square root of negative numbers to exist in mathematics.
In practical terms, when you see a negative number under a square root, like \( \sqrt{-8} \) in our exercise, you can think of it as involving the imaginary unit. Here's how it works:
In practical terms, when you see a negative number under a square root, like \( \sqrt{-8} \) in our exercise, you can think of it as involving the imaginary unit. Here's how it works:
- First, break down the negative square root into two parts: the square root of the positive number, and the square root of negative one. So, \( \sqrt{-8} \) becomes \( \sqrt{8} \cdot i \).
- The \( \sqrt{8} \) can be simplified further, usually into something smaller and more recognizable, such as \( 2\sqrt{2} \), keeping the \( i \) next to it.
Simplify Expressions
Simplifying expressions with complex numbers often means exactly that: making them simpler and easier to understand. This usually involves breaking down larger components into smaller steps, just like we did in the exercise.
Here’s a step-by-step for simplifying \( \frac{4-\sqrt{-8}}{2} \):
Here’s a step-by-step for simplifying \( \frac{4-\sqrt{-8}}{2} \):
- Start by addressing any roots involving negative numbers using the imaginary unit \( i \). For \( \sqrt{-8} \), rewrite it as \( 2\sqrt{2}i \).
- Substitute this back into the entire expression, giving you: \( \frac{4 - 2\sqrt{2}i}{2} \).
- Then, break down the main fraction into two separate fractions: \( \frac{4}{2} - \frac{2\sqrt{2}i}{2} \).
- Simplify these fractions to get the neatest form. \( \frac{4}{2} \) results in \( 2 \) and \( \frac{2\sqrt{2}i}{2} \) results in \( \sqrt{2}i \).
Algebraic Form \(a+bi\)
Expressing complex numbers in the form \(a + bi\) is key for clarity and comparison. The format shows two parts:
In our example, once simplified, we expressed our result as \( 2 - \sqrt{2}i \).
This is already in the form \( a + bi \), showing the real part as 2 and the imaginary part as \( -\sqrt{2} \).
The main takeaway is that the \( a + bi \) form makes it easy to quickly identify each part of the complex number and how they interrelate. It's a foundation for further calculations, making it a vital part of any complex number work.
- \( a \) represents the real component.
- \( b \) is the coefficient of the imaginary part, showing how many multiples of \( i \) are involved.
In our example, once simplified, we expressed our result as \( 2 - \sqrt{2}i \).
This is already in the form \( a + bi \), showing the real part as 2 and the imaginary part as \( -\sqrt{2} \).
The main takeaway is that the \( a + bi \) form makes it easy to quickly identify each part of the complex number and how they interrelate. It's a foundation for further calculations, making it a vital part of any complex number work.