Answer: -1 < a < 3.
- A -1 < a < 3
- B 1 < a < 3
- C -1 < a < 5
- D 0 < a < 4
Correct answer: A. -1 < a < 3
Explanation: Factor: (x-a)²=1, so roots are x=a+1 and x=a-1. Both must lie in (-2,4): a-1 > -2 gives a > -1; a+1 < 4 gives a < 3. Combining both conditions: -1 < a < 3. Answer: -1 < a < 3
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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