In Exercises 1–3, perform the indicated operations and write the result in standard form. (6 − 7i)(2 + 5i)
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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 3
Textbook Question
In Exercises 1–3, perform the indicated operations and write the result in standard form. ___ ___ 2√−49 + 3√−64
Verified step by step guidance1
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: \(2\sqrt{-49} = 2\sqrt{49} \times i\) and \(3\sqrt{-64} = 3\sqrt{64} \times i\).
Calculate the square roots of the positive numbers: \(\sqrt{49} = 7\) and \(\sqrt{64} = 8\).
Substitute these values back into the expression: \(2 \times 7 \times i + 3 \times 8 \times i\).
Combine like terms by factoring out \(i\): \((2 \times 7 + 3 \times 8) i\), which simplifies to \((14 + 24) i\). This is the expression in standard form \(a + bi\), where \(a\) is the real part and \(b\) is the coefficient of the imaginary part.
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Imaginary Numbers and the Imaginary Unit i
Imaginary numbers arise when taking the square root of negative numbers, which is not defined in the real number system. The imaginary unit i is defined as √(-1), allowing us to express roots of negative numbers as multiples of i, such as √(-49) = 7i.
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Imaginary Roots with the Square Root Property
Simplifying Radicals Involving Negative Numbers
To simplify radicals with negative radicands, factor out the negative sign as i² or i, then simplify the positive part. For example, √(-64) = √(64) × √(-1) = 8i. This process helps convert complex radicals into a standard form involving real and imaginary parts.
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Dividing Complex Numbers
Standard Form of Complex Numbers
The standard form of a complex number is a + bi, where a and b are real numbers and i is the imaginary unit. After performing operations on imaginary numbers, results should be expressed in this form to clearly separate the real and imaginary components.
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Complex Numbers In Polar Form
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