All flashcards Flashcard 1: Identify whether 3 + 0 i 3+0i 3 + 0 i is real, imaginary, or complex with nonzero parts. Answer: Real number. Has zero imaginary part, so it's real.
Flashcard 2: What is the real part of the complex number a + b i a+bi a + bi ? Answer: Re ( a + b i ) = a \operatorname{Re}(a+bi)=a Re ( a + bi ) = a . The real part is the coefficient of the constant term.
Flashcard 3: What is the imaginary part of − 6 + 11 i -6+11i − 6 + 11 i ? Answer: 11 11 11 . The imaginary part is the coefficient of i i i .
Flashcard 4: What is ( − i ) 2 (-i)^2 ( − i ) 2 simplified? Answer: − 1 -1 − 1 . ( − i ) 2 = ( − 1 ) 2 ⋅ i 2 = 1 ⋅ ( − 1 ) = − 1 (-i)^2 = (-1)^2 \cdot i^2 = 1 \cdot (-1) = -1 ( − i ) 2 = ( − 1 ) 2 ⋅ i 2 = 1 ⋅ ( − 1 ) = − 1
Flashcard 5: What is − 9 \sqrt{-9} − 9 written using i i i ? Answer: 3 i 3i 3 i . − 9 = 9 ⋅ − 1 = 3 i \sqrt{-9} = \sqrt{9} \cdot \sqrt{-1} = 3i − 9 = 9 ⋅ − 1 = 3 i
Flashcard 6: What is − 16 \sqrt{-16} − 16 written using i i i ? Answer: 4 i 4i 4 i . − 16 = 16 ⋅ − 1 = 4 i \sqrt{-16} = \sqrt{16} \cdot \sqrt{-1} = 4i − 16 = 16 ⋅ − 1 = 4 i
Flashcard 7: What is − 25 \sqrt{-25} − 25 written using i i i ? Answer: 5 i 5i 5 i . − 25 = 25 ⋅ − 1 = 5 i \sqrt{-25} = \sqrt{25} \cdot \sqrt{-1} = 5i − 25 = 25 ⋅ − 1 = 5 i
Flashcard 8: What is − 49 \sqrt{-49} − 49 written using i i i ? Answer: 7 i 7i 7 i . − 49 = 49 ⋅ − 1 = 7 i \sqrt{-49} = \sqrt{49} \cdot \sqrt{-1} = 7i − 49 = 49 ⋅ − 1 = 7 i
Flashcard 9: What is − 64 \sqrt{-64} − 64 written using i i i ? Answer: 8 i 8i 8 i . − 64 = 64 ⋅ − 1 = 8 i \sqrt{-64} = \sqrt{64} \cdot \sqrt{-1} = 8i − 64 = 64 ⋅ − 1 = 8 i
Flashcard 10: What is − 81 \sqrt{-81} − 81 written using i i i ? Answer: 9 i 9i 9 i . − 81 = 81 ⋅ − 1 = 9 i \sqrt{-81} = \sqrt{81} \cdot \sqrt{-1} = 9i − 81 = 81 ⋅ − 1 = 9 i
Flashcard 11: What is − 100 \sqrt{-100} − 100 written using i i i ? Answer: 10 i 10i 10 i . − 100 = 100 ⋅ − 1 = 10 i \sqrt{-100} = \sqrt{100} \cdot \sqrt{-1} = 10i − 100 = 100 ⋅ − 1 = 10 i
Flashcard 12: What is − 4 \sqrt{-4} − 4 written using i i i ? Answer: 2 i 2i 2 i . − 4 = 4 ⋅ − 1 = 2 i \sqrt{-4} = \sqrt{4} \cdot \sqrt{-1} = 2i − 4 = 4 ⋅ − 1 = 2 i
Flashcard 13: What is − 36 \sqrt{-36} − 36 written using i i i ? Answer: 6 i 6i 6 i . − 36 = 36 ⋅ − 1 = 6 i \sqrt{-36} = \sqrt{36} \cdot \sqrt{-1} = 6i − 36 = 36 ⋅ − 1 = 6 i
Flashcard 14: What is − 121 \sqrt{-121} − 121 written using i i i ? Answer: 11 i 11i 11 i . − 121 = 121 ⋅ − 1 = 11 i \sqrt{-121} = \sqrt{121} \cdot \sqrt{-1} = 11i − 121 = 121 ⋅ − 1 = 11 i
Flashcard 15: Which statement is true about a a a and b b b in a + b i a+bi a + bi ? Answer: a a a and b b b are real numbers. Both coefficients must be real for complex form.
Flashcard 16: What condition on b b b makes a + b i a+bi a + bi a real number? Answer: b = 0 b=0 b = 0 . When imaginary part is zero, number is real.
Flashcard 17: What condition on a a a makes a + b i a+bi a + bi a pure imaginary number? Answer: a = 0 a=0 a = 0 . When real part is zero, number is pure imaginary.
Flashcard 18: What is ( − i ) 3 (-i)^3 ( − i ) 3 simplified? Answer: i i i . ( − i ) 3 = ( − 1 ) 3 ⋅ i 3 = − 1 ⋅ ( − i ) = i (-i)^3 = (-1)^3 \cdot i^3 = -1 \cdot (-i) = i ( − i ) 3 = ( − 1 ) 3 ⋅ i 3 = − 1 ⋅ ( − i ) = i
Flashcard 19: What is 1 i \frac{1}{i} i 1 simplified in terms of i i i ? Answer: − i -i − i . Multiply by − i − i \frac{-i}{-i} − i − i to get − i 1 = − i \frac{-i}{1} = -i 1 − i = − i
Flashcard 20: What are the two real-number components in the complex form a + b i a+bi a + bi ? Answer: a a a is real part; b b b is imaginary coefficient. Standard complex form separates real and imaginary components.
Flashcard 21: What is the imaginary unit written as a complex number in a + b i a+bi a + bi form? Answer: i = 0 + 1 i i=0+1i i = 0 + 1 i . Pure imaginary unit with zero real part.
Flashcard 22: Identify a a a and b b b for the complex number 7 − 2 i 7-2i 7 − 2 i in the form a + b i a+bi a + bi . Answer: a = 7 , b = − 2 a=7,\ b=-2 a = 7 , b = − 2 . Real part is 7, imaginary coefficient is -2.
Flashcard 23: Identify a a a and b b b for the complex number − 4 + 9 i -4+9i − 4 + 9 i in the form a + b i a+bi a + bi . Answer: a = − 4 , b = 9 a=-4,\ b=9 a = − 4 , b = 9 . Real part is -4, imaginary coefficient is 9.
Flashcard 24: What is i 2 i^2 i 2 ? Answer: − 1 -1 − 1 . By definition of the imaginary unit.
Flashcard 25: What is i 4 i^4 i 4 simplified? Answer: 1 1 1 . i 4 = ( i 2 ) 2 = ( − 1 ) 2 = 1 i^4 = (i^2)^2 = (-1)^2 = 1 i 4 = ( i 2 ) 2 = ( − 1 ) 2 = 1
Flashcard 26: What is i 7 i^7 i 7 simplified? Answer: − i -i − i . i 7 = i 4 ⋅ i 3 = 1 ⋅ ( − i ) = − i i^7 = i^4 \cdot i^3 = 1 \cdot (-i) = -i i 7 = i 4 ⋅ i 3 = 1 ⋅ ( − i ) = − i
Flashcard 27: What is ( − i ) 3 (-i)^3 ( − i ) 3 simplified? Answer: i i i . ( − i ) 3 = ( − 1 ) 3 ⋅ i 3 = − 1 ⋅ ( − i ) = i (-i)^3 = (-1)^3 \cdot i^3 = -1 \cdot (-i) = i ( − i ) 3 = ( − 1 ) 3 ⋅ i 3 = − 1 ⋅ ( − i ) = i
Flashcard 28: What is i 3 i^3 i 3 simplified using i 2 = − 1 i^2=-1 i 2 = − 1 ? Answer: − i -i − i . i 3 = i 2 ⋅ i = − 1 ⋅ i = − i i^3 = i^2 \cdot i = -1 \cdot i = -i i 3 = i 2 ⋅ i = − 1 ⋅ i = − i
Flashcard 29: What is − 81 \sqrt{-81} − 81 written using i i i ? Answer: 9 i 9i 9 i . − 81 = 81 ⋅ − 1 = 9 i \sqrt{-81} = \sqrt{81} \cdot \sqrt{-1} = 9i − 81 = 81 ⋅ − 1 = 9 i
Flashcard 30: What is − 121 \sqrt{-121} − 121 written using i i i ? Answer: 11 i 11i 11 i . − 121 = 121 ⋅ − 1 = 11 i \sqrt{-121} = \sqrt{121} \cdot \sqrt{-1} = 11i − 121 = 121 ⋅ − 1 = 11 i