Chapter 10: Problem 67
Perform the indicated operation and simplify. Write each answer in the form \(a+b i\) $$ \frac{2}{3-2 i} $$
Short Answer
Expert verified
\(\frac{6}{13} + \frac{4}{13}i\)
Step by step solution
01
- Identify the Conjugate
To rationalize the denominator, identify the conjugate of the denominator. The conjugate of \(3 - 2i\) is \(3 + 2i\).
02
- Multiply by the Conjugate
Multiply both the numerator and the denominator by the conjugate obtained in Step 1: \[\frac{2}{3-2i} \times \frac{3+2i}{3+2i} = \frac{2(3+2i)}{(3-2i)(3+2i)}\]
03
- Distribute in the Numerator
Distribute the numerator: \[2(3 + 2i) = 6 + 4i\]
04
- Simplify the Denominator
Simplify the denominator using the difference of squares formula: \[(3-2i)(3+2i) = 9 - (2i)^2 = 9 - 4(-1) = 9 + 4 = 13\]
05
- Combine Numerator and Denominator
Combine the simplified numerator and denominator: \[\frac{6 + 4i}{13}\]
06
- Simplify the Fraction
Simplify the expression by dividing each part of the numerator by the denominator: \[\frac{6}{13} + \frac{4i}{13} = \frac{6}{13} + \frac{4}{13}i\]
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Rationalizing Denominators
Rationalizing the denominator involves eliminating any complex number in the denominator from a fraction. We do this because it makes computations easier and fractions more presentable. To rationalize a denominator in a fraction with a complex number, we need to multiply both the numerator and the denominator by the conjugate of the complex denominator.
Let's consider our example: \(\frac{2}{3-2i}\). Here, the denominator is the complex number \((3-2i)\).
The conjugate of \((3-2i)\) is \((3+2i)\). Next, we'll multiply the numerator and the denominator by this conjugate. Always remember, multiplying by the conjugate helps to convert a complex denominator into a real number.
Let's consider our example: \(\frac{2}{3-2i}\). Here, the denominator is the complex number \((3-2i)\).
The conjugate of \((3-2i)\) is \((3+2i)\). Next, we'll multiply the numerator and the denominator by this conjugate. Always remember, multiplying by the conjugate helps to convert a complex denominator into a real number.
Conjugate in Complex Numbers
A conjugate in complex numbers is formed by changing the sign between the real part and the imaginary part of the number. If you have a complex number \((a + bi)\), its conjugate is \((a - bi)\).
In our exercise, we initially had \((3 - 2i)\). Its conjugate is \((3 + 2i)\).
This method helps in transforming complex division into a simpler multiplication and addition problem using the difference of squares. Here's the important part: when a complex number is multiplied by its conjugate, the result is a real number.
Notice how the imaginary parts are effectively eliminated, leaving a nice real number.
In our exercise, we initially had \((3 - 2i)\). Its conjugate is \((3 + 2i)\).
This method helps in transforming complex division into a simpler multiplication and addition problem using the difference of squares. Here's the important part: when a complex number is multiplied by its conjugate, the result is a real number.
- For example, \((3 - 2i)(3 + 2i) = 9 + 4 = 13\).
Notice how the imaginary parts are effectively eliminated, leaving a nice real number.
Simplifying Complex Fractions
After multiplying and distributing, we end up with a new fraction, like \(\frac{6 + 4i}{13}\) in our case.
The goal is to express the answer in the form \((a + bi)\), where both parts are rational numbers. To achieve this, split the fraction: \(\frac{6 + 4i}{13} = \frac{6}{13} + \frac{4i}{13}\).
So the simplified form will be \(\frac{6}{13} + \frac{4}{13}i\).
This method of dealing with complex numbers is very handy in algebra and higher mathematics. It reduces complex division to a series of straightforward multiplication and addition steps, ensuring we end up with a standard form of a complex number. Don't forget, practice makes perfect!
The goal is to express the answer in the form \((a + bi)\), where both parts are rational numbers. To achieve this, split the fraction: \(\frac{6 + 4i}{13} = \frac{6}{13} + \frac{4i}{13}\).
So the simplified form will be \(\frac{6}{13} + \frac{4}{13}i\).
This method of dealing with complex numbers is very handy in algebra and higher mathematics. It reduces complex division to a series of straightforward multiplication and addition steps, ensuring we end up with a standard form of a complex number. Don't forget, practice makes perfect!