Answer: 19.
- A 19
- B 16
- C 21
- D 13
Correct answer: A. 19
Explanation: Alpha² + beta² = (alpha+beta)² - 2(alpha×beta) = 25 - 6 = 19.
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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