Answer: -4.
- A 4
- B -4
- C 4i
- D -4i
Correct answer: B. -4
Explanation: z2 = (1-i)2 = 1 - 2i + i2 = 1 - 2i - 1 = -2i. z4 = (-2i)2 = 4i2 = -4.
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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