In Exercises 1–10, perform the indicated operations and write the result in standard form. (7 + 8i)(7 − 8i)
Ch. 5 - Complex Numbers, Polar Coordinates and Parametric Equations

모든 교과서
Blitzer 3rd Edition
Ch. 5 - Complex Numbers, Polar Coordinates and Parametric Equations
문제 5.1.57
Blitzer 3rd Edition
Ch. 5 - Complex Numbers, Polar Coordinates and Parametric Equations
문제 5.1.575장, 문제 5.1.57
In Exercises 53–58, perform the indicated operation(s) and write the result in standard form. ___ ___ 5√(−16) + 3√(−81)
검증된 단계별 안내1
Recognize that the expressions involve square roots of negative numbers, which means we are dealing with imaginary numbers. Recall that \(\sqrt{-a} = \sqrt{a} \times i\), where \(i\) is the imaginary unit with the property \(i^2 = -1\).
Rewrite each term by separating the negative sign inside the square root: \(5\sqrt{-16} = 5 \times \sqrt{16} \times i\) and \(3\sqrt{-81} = 3 \times \sqrt{81} \times i\).
Calculate the square roots of the positive numbers: \(\sqrt{16} = 4\) and \(\sqrt{81} = 9\), so the terms become \(5 \times 4 \times i\) and \(3 \times 9 \times i\) respectively.
Multiply the coefficients: \(5 \times 4 = 20\) and \(3 \times 9 = 27\), so the expression is now \(20i + 27i\).
Combine like terms (both are imaginary terms) by adding the coefficients: \(20i + 27i = (20 + 27)i\), which simplifies to \$47i\(. This is the expression in standard form, where the real part is 0 and the imaginary part is \)47i$.

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주요 개념
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Complex Numbers and Imaginary Unit
Complex numbers include a real part and an imaginary part, where the imaginary unit 'i' is defined as √−1. When dealing with square roots of negative numbers, express them in terms of 'i' to simplify and perform operations.
추천 영상:
Introduction to Complex Numbers
Simplifying Square Roots of Negative Numbers
To simplify √−a, rewrite it as √a × √−1, which equals √a × i. For example, √−16 becomes 4i. This allows you to convert roots of negative numbers into imaginary numbers for further calculation.
추천 영상:
Imaginary Roots with the Square Root Property
Standard Form of Complex Numbers
The standard form of a complex number is a + bi, where 'a' is the real part and 'b' is the coefficient of the imaginary part. After performing operations, express the result in this form for clarity and consistency.
추천 영상:
Complex Numbers In Polar Form
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