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Ch. 5 - Complex Numbers, Polar Coordinates and Parametric Equations
Blitzer - Trigonometry 3rd Edition
Blitzer3rd EditionTrigonometryISBN: 9780137316601당신이 사용하는 게 아니라요?교과서 변경
5장, 문제 5.1.59

Evaluate x² − 2x + 2 for x = 1 + i.

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Recognize that the problem involves evaluating the expression \(x^2 - 2x + 2\) where \(x\) is a complex number, specifically \(x = 1 + i\), with \(i\) being the imaginary unit satisfying \(i^2 = -1\).
Substitute \(x = 1 + i\) into the expression to get: \((1 + i)^2 - 2(1 + i) + 2\).
Expand the squared term using the formula \((a + b)^2 = a^2 + 2ab + b^2\): \((1 + i)^2 = 1^2 + 2 \cdot 1 \cdot i + i^2 = 1 + 2i + i^2\).
Replace \(i^2\) with \(-1\) and simplify the expression inside the parentheses: \(1 + 2i + (-1) = 2i\).
Now, substitute back and simplify the entire expression step-by-step: \(2i - 2(1 + i) + 2\). Expand the multiplication and combine like terms to simplify the expression fully.

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주요 개념

질문에 올바르게 답하기 위해 반드시 이해해야 하는 핵심 개념들은 다음과 같습니다.

Complex Numbers

Complex numbers are numbers of the form a + bi, where a and b are real numbers and i is the imaginary unit with the property i² = -1. Understanding how to perform arithmetic operations with complex numbers is essential for evaluating expressions involving them.
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Dividing Complex Numbers

Substitution in Algebraic Expressions

Substitution involves replacing a variable in an expression with a given value. In this case, substituting the complex number x = 1 + i into the polynomial allows evaluation of the expression for that specific input.
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Simplifying Trig Expressions

Simplification of Expressions with Imaginary Units

Simplifying expressions with imaginary units requires applying the rule i² = -1 and combining like terms carefully. This process ensures the expression is reduced to its simplest form, often resulting in a complex number in standard form a + bi.
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Imaginary Roots with the Square Root Property