Chapter 1: Problem 60
Find all solutions of the equation, and express them in the form \(a+b i\) $$ x^{2}+2 x+2=0 $$
Short Answer
Expert verified
The solutions are \( x = -1 + i \) and \( x = -1 - i \).
Step by step solution
01
Identify the Coefficients
The given quadratic equation is \( x^2 + 2x + 2 = 0 \). Identify the coefficients: \( a = 1 \), \( b = 2 \), and \( c = 2 \).
02
Use the Quadratic Formula
Recall the quadratic formula: \( x = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a} \). We will use this formula to find the roots of the quadratic equation.
03
Calculate the Discriminant
The discriminant \( \Delta \) is given by \( b^2 - 4ac \). Substitute the values of \( a \), \( b \), and \( c \): \( \Delta = 2^2 - 4 \times 1 \times 2 = 4 - 8 = -4 \).
04
Compute the Square Root of the Discriminant
Since the discriminant \( \Delta = -4 \) is negative, the solutions will involve complex numbers. Compute \( \sqrt{-4} = 2i \).
05
Substitute into the Quadratic Formula
Substitute \( b = 2 \), \( a = 1 \), and \( \sqrt{\Delta} = 2i \) into the quadratic formula:\[ x = \frac{-2 \pm 2i}{2 \times 1} = \frac{-2 \pm 2i}{2} \].
06
Simplify the Expression
Simplify the expression to find the solutions:\[ x = \frac{-2}{2} \pm \frac{2i}{2} = -1 \pm i \].Thus, the solutions are \( x = -1 + i \) and \( x = -1 - i \).
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Understanding Quadratic Equations
A quadratic equation is a polynomial equation of the second degree. It is generally written in the form \( ax^2 + bx + c = 0 \), where \( a \), \( b \), and \( c \) are constants, and \( a eq 0 \). In our exercise, the quadratic equation is \( x^2 + 2x + 2 = 0 \). Here:
- \( a = 1 \)
- \( b = 2 \)
- \( c = 2 \)
Exploring the Quadratic Formula
The quadratic formula is a practical tool to solve any quadratic equation. It is expressed as:\[x = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a}\]In this formula, the term \( b \) and \( 4ac \) come from the standard form of the quadratic equation. To find solutions:
- Calculate the discriminant \( b^2 - 4ac \).
- Inspect its sign to determine the nature of solutions: positive for two real solutions, zero for one real solution, and negative for complex solutions.
- Substitute \( a \), \( b \), and \( c \) into the formula and solve for \( x \).
Delving Into Complex Solutions
Complex solutions occur when the discriminant of a quadratic equation is negative. Such solutions are made up of a real part and an imaginary part. Imaginary numbers are expressed with the unit \( i \), defined by \( i^2 = -1 \).
In our problem, the discriminant is \(-4\), which translates into an imaginary number when taking the square root. We find \( \sqrt{-4} = 2i \). Thus, the solutions are complex:
In our problem, the discriminant is \(-4\), which translates into an imaginary number when taking the square root. We find \( \sqrt{-4} = 2i \). Thus, the solutions are complex:
- For \( x = \frac{-b + \sqrt{b^2 - 4ac}}{2a} \), we get \(-1 + i \).
- For \( x = \frac{-b - \sqrt{b^2 - 4ac}}{2a} \), we get \(-1 - i \).