Answer: i.
- A -i
- B 1
- C 2i
- D i
Correct answer: D. i
Explanation: z<sub>1</sub>/z<sub>2</sub> = (1+i)/(1-i). Multiply by (1+i)/(1+i): (1+i)<sup>2</sup>/2 = 2i/2 = i.
A complex number z = a+ib is plotted as a point (or vector from the origin) on the Argand plane, with the real part along the horizontal axis and the imaginary part along the vertical; its modulus |z| is the vector's length, and its argument θ is the angle from the positive real axis.
Concept context
Complex numbers in a+ib form, modulus, argument, polar form, cube roots of unity, and quadratic equations with complex roots
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