All flashcards
Flashcard 1: What is (1−2i)(−4+3i) in standard form?
Answer: 2+11i. Use FOIL: (1)(−4)+(1)(3i)+(−2i)(−4)+(−2i)(3i)=−4+3i+8i+6.
Flashcard 2: What is (10−3i)−(4+9i) in standard form?
Answer: 6−12i. Subtract real parts: 10−4=6, imaginary parts: −3−9=−12.
Flashcard 3: What is (bi)(di) simplified using i2=−1?
Answer: −bd. Since (bi)(di)=bdi2=bd(−1)=−bd.
Flashcard 4: What is the value of i3 written in simplest form?
Answer: −i. Since i3=i2⋅i=(−1)⋅i=−i.
Flashcard 5: What is the additive identity for complex numbers?
Answer: 0+0i. Adding this to any complex number yields the same number.
Flashcard 6: What is the difference (a+bi)−(c+di) in standard form?
Answer: (a−c)+(b−d)i. Subtract real parts and imaginary parts separately.
Flashcard 7: What is (3+2i)+(5−7i) in standard form?
Answer: 8−5i. Add real parts: 3+5=8, imaginary parts: 2+(−7)=−5.
Flashcard 8: What is the product (a+bi)(c+di) in standard form?
Answer: (ac−bd)+(ad+bc)i. Use FOIL and i2=−1 to simplify.
Flashcard 9: What is the value of i2?
Answer: −1. By definition of the imaginary unit.
Flashcard 10: What is (a+bi)+(c−di) simplified in standard form?
Answer: (a+c)+(b−d)i. Add real parts and subtract imaginary parts.
Flashcard 11: What is (a+bi)−(c−di) simplified in standard form?
Answer: (a−c)+(b+d)i. Distribute the negative sign to both terms inside parentheses.
Flashcard 12: What is (a+bi)(a−bi) simplified using i2=−1?
Answer: a2+b2. Conjugate multiplication yields sum of squares.
Flashcard 13: What is (4+3i)(4−3i) in standard form?
Answer: 25. Difference of squares: (4)2−(3i)2=16−9i2=16+9=25.
Flashcard 14: What is (3−2i)(−1+i) in standard form?
Answer: −1+5i. Use FOIL: (3)(−1)+(3)(i)+(−2i)(−1)+(−2i)(i)=−3+3i+2i+2.
Flashcard 15: What is the value of i5 written in simplest form?
Answer: i. Since i5=i4⋅i=1⋅i=i.
Flashcard 16: What is (7i)(−3i) simplified?
Answer: 21. Since (7i)(−3i)=−21i2=−21(−1)=21.
Flashcard 17: What is the sum (a+bi)+(c+di) in standard form?
Answer: (a+c)+(b+d)i. Add real parts and imaginary parts separately.
Flashcard 18: What is the value of i2?
Answer: −1. By definition of the imaginary unit.
Flashcard 19: What is (a+bi)(a−bi) simplified using i2=−1?
Answer: a2+b2. Conjugate multiplication yields sum of squares.
Flashcard 20: What is (−3+4i)−(8+i) in standard form?
Answer: −11+3i. Subtract real parts: −3−8=−11, imaginary parts: 4−1=3.
Flashcard 21: What is the real part of the complex number a+bi?
Answer: a. The coefficient of the non-imaginary term.
Flashcard 22: What is (1+i)(1+i) in standard form?
Answer: 2i. Use FOIL: (1)(1)+(1)(i)+(i)(1)+(i)(i)=1+i+i−1=2i.
Flashcard 23: What is the value of i6 written in simplest form?
Answer: −1. Since i6=(i2)3=(−1)3=−1.
Flashcard 24: What is (5−2i)(1+3i) in standard form?
Answer: 11+13i. Use FOIL: (5)(1)+(5)(3i)+(−2i)(1)+(−2i)(3i)=5+15i−2i+6.
Flashcard 25: What is (2+5i)(−3−2i) in standard form?
Answer: 4−19i. Use FOIL: (2)(−3)+(2)(−2i)+(5i)(−3)+(5i)(−2i)=−6−4i−15i−10.
Flashcard 26: What is (8+0i)−(3+0i) in standard form?
Answer: 5. Subtract real parts only: 8−3=5, imaginary parts are zero.
Flashcard 27: What is (−5i)+(12i) in standard form?
Answer: 7i. Add imaginary parts: −5i+12i=7i.
Flashcard 28: What is (1−i)(1−i) in standard form?
Answer: −2i. Use FOIL: (1)(1)+(1)(−i)+(−i)(1)+(−i)(−i)=1−i−i−1=−2i.
Flashcard 29: What is (1+i)(1−i) in standard form?
Answer: 2. Difference of squares: (1)2−(i)2=1−i2=1+1=2.
Flashcard 30: What is (2−i)(−5−i) in standard form?
Answer: −11+3i. Use FOIL: (2)(−5)+(2)(−i)+(−i)(−5)+(−i)(−i)=−10−2i+5i−1.