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Complex Numbers (Standard)

Multi-step exam-style items.

Phase 2 · JEE

Complex Numbers: core idea

Polar multiplication.

Example problem: hint and answer

(2+i)(3−i)(2+i)(3-i): real part?

Hint: Expand. Answer: 7.

Practice (9 problems — type your answers)

  • 1. (1+i)/(1−i)(1+i)/(1-i): imaginary part?

  • 2. Roots of z2−2z+5=0z^2-2z+5=0: real part?

  • 3. ∣1+i∣|1+i|?

  • 4. (1+i)4(1+i)^4?

  • 5. Locus ∣z−1∣=2|z-1|=2: radius?

  • 6. Cube roots of unity: sum?

  • 7. z+zˉ=4z+\bar z=4: Re(z)(z)?

  • 8. ∣z∣2|z|^2 for z=3+4iz=3+4i?

  • 9. De Moivre: (cos⁡θ+isin⁡θ)2(\cos\theta+i\sin\theta)^2 real part equals cos⁡(kθ)\cos(k\theta) with k=k=?

Complex Numbers Practice Problems — Standard