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Complex numbers

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Intro to the imaginary numbersIntro to the imaginary numbersSimplifying roots of negative numbersPowers of the imaginary unitPowers of the imaginary uniti as the principal root of -1
Practice
Simplify roots of negative numbersGet 3 of 4 questions to level up!
Powers of the imaginary unitGet 3 of 4 questions to level up!
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Intro to complex numbersIntro to complex numbersClassifying complex numbers
Practice
Parts of complex numbersGet 3 of 4 questions to level up!
Classify complex numbersGet 3 of 4 questions to level up!
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Plotting numbers on the complex planeThe complex plane
Practice
Plot numbers on the complex planeGet 3 of 4 questions to level up!
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Adding complex numbersSubtracting complex numbers
Practice
Add & subtract complex numbersGet 3 of 4 questions to level up!
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Multiplying complex numbersMultiplying complex numbersComplex number operations review
Practice
Multiply complex numbers (basic)Get 3 of 4 questions to level up!
Multiply complex numbersGet 3 of 4 questions to level up!
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Solving quadratic equations: complex roots
Practice

About this unit

Complex numbers are built on the idea that we can define the number i (called "the imaginary unit") to be the principal square root of -1, or a solution to the equation x²=-1. From this starting point evolves a rich and exciting world of the number system that encapsulates everything we have known before: integers, rational, and real numbers.