Multiplying Complex Numbers

Front

What is a complex number?

Back

A complex number is a number that can be expressed in the form a + bi, where a and b are real numbers, and i is the imaginary unit, defined as the square root of -1.

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CCSS.HSN.CN.A.1

Front

What is the imaginary unit 'i'?

Back

The imaginary unit 'i' is defined as i = √(-1). It is used to extend the real number system to include solutions to equations that do not have real solutions.

Tags

CCSS.HSN.CN.A.1

Front

How do you multiply two complex numbers?

Back

To multiply two complex numbers (a + bi) and (c + di), use the distributive property: (a + bi)(c + di) = ac + adi + bci + bdi². Remember that i² = -1.

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CCSS.HSN.CN.A.2

Front

What is the result of multiplying (5 - 4i) and (-3 - 6i)?

Back

The result is 54 - 363i.

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CCSS.HSN.CN.C.8

Front

What is the result of multiplying (5 - i) by itself?

Back

The result is 24 - 10i.

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CCSS.HSN.CN.C.8

Front

What is the product of (i)(3i)?

Back

The product is -3.

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CCSS.HSN.CN.A.2

Front

What is the product of (-4i)(3i)(4i)?

Back

The product is 48i.

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CCSS.HSN.CN.A.2

Front

What is the conjugate of a complex number a + bi?

Back

The conjugate of a complex number a + bi is a - bi.

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CCSS.HSN.CN.A.3

Front

How does multiplying by the conjugate help in division of complex numbers?

Back

Multiplying by the conjugate helps eliminate the imaginary part in the denominator, making it a real number.

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CCSS.HSN.CN.A.3

Front

What is the modulus of a complex number a + bi?

Back

The modulus of a complex number a + bi is given by √(a² + b²). It represents the distance from the origin in the complex plane.