1.1 Writing Complex Numbers

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Warm Up for 1.1 in Math 2
12 3 5
ANSWER
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1.1 (M2)Writing Complex Numbers
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Solve x2 4 0

• x2 -4
• x v(-4)
• In the real number system, there isnt a number
  we can square to get -4.
• Imaginary numbers Dont think of them as not
  real
• Mathematicians chose this term for the pattern to
  describe the square root of a negative number
  after they thought all real numbers were
  identified

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Complex Numbers (a bi)

• Real Numbers
• (a 0i)
• -1 ½
• pi v3

Imaginary Numbers (a bi, b ? 0) 2 3i 5-5i
Pure Imaginary Numbers (0 bi, b ? 0) -4i 5i
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How do we write the square root of a negative
number?

• v-1 is called i or an imaginary unitit is a way
  to describe the square root of a negative number
• (v-1 )2
• v-1 v-1
• Therefore, i2 -1.
• i v-1 i2 -1

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Write the complex number in standard form.

• 1. v-1 2. v-25
• i 5i
• 3. 2 - v-9 4. 7 - v-27
• 2 -3i 7-3iv3

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• Find real numbers x and y to make the equation
  true.
• -3x 2yi 15 4i
• 11 5yi x 10i
• 22 8i 11x 4yi