In Exercises 1–10, perform the indicated operations and write the result in standard form. (7 + 8i)(7 − 8i)
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- 0. Review of College Algebra4h 45m
- 1. Measuring Angles40m
- 2. Trigonometric Functions on Right Triangles2h 5m
- 3. Unit Circle1h 19m
- 4. Graphing Trigonometric Functions1h 19m
- 5. Inverse Trigonometric Functions and Basic Trigonometric Equations1h 41m
- 6. Trigonometric Identities and More Equations2h 34m
- 7. Non-Right Triangles1h 38m
- 8. Vectors2h 25m
- 9. Polar Equations2h 5m
- 10. Parametric Equations1h 6m
- 11. Graphing Complex Numbers1h 7m
11. Graphing Complex Numbers
Graphing Complex Numbers
Problem 8
Textbook Question
Perform the indicated operations and write the result in standard form. √−32 − √−18
Verified step by step guidance1
Recognize that the square roots of negative numbers involve imaginary numbers. Recall that \(\sqrt{-a} = \sqrt{a} \times i\), where \(i = \sqrt{-1}\).
Rewrite each term using the imaginary unit \(i\): \(\sqrt{-32} = \sqrt{32} \times i\) and \(\sqrt{-18} = \sqrt{18} \times i\).
Simplify the square roots of the positive numbers under the radicals by factoring out perfect squares: \(\sqrt{32} = \sqrt{16 \times 2} = 4\sqrt{2}\) and \(\sqrt{18} = \sqrt{9 \times 2} = 3\sqrt{2}\).
Substitute the simplified forms back into the expression: \(4\sqrt{2}i - 3\sqrt{2}i\).
Combine like terms by factoring out \(\sqrt{2}i\): \((4 - 3)\sqrt{2}i\), which simplifies to \(1 \times \sqrt{2}i\), or simply \(\sqrt{2}i\).
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Imaginary Numbers and Complex Numbers
Imaginary numbers arise from the square roots of negative numbers, defined using the imaginary unit i, where i² = -1. Complex numbers combine real and imaginary parts in the form a + bi. Understanding this allows you to rewrite √-32 and √-18 in terms of i.
Recommended video:
Introduction to Complex Numbers
Simplifying Square Roots
Simplifying square roots involves factoring the radicand into perfect squares and other factors. For example, √32 can be simplified to 4√2 because 16 is a perfect square. This process helps in expressing the terms in a simpler form before performing operations.
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Imaginary Roots with the Square Root Property
Operations with Complex Numbers
Adding or subtracting complex numbers requires combining like terms: real parts with real parts and imaginary parts with imaginary parts. After simplifying the square roots, you perform the indicated subtraction by handling the imaginary components accordingly to write the result in standard form a + bi.
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Dividing Complex Numbers
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