Answer: [-1, 1].
- A x = 0 only
- B [-1, 1]
- C {-1, 1}
- D All real x
Correct answer: B. [-1, 1]
Explanation: Case analysis on |x|: Case 1: x < -1: (1-x)+(-x-1)=-2x=2, x=-1 (boundary). Case 2: -1≤x≤1: (1-x)+(x+1)=2=2, always true. Case 3: x>1: (x-1)+(x+1)=2x=2, x=1 (boundary). So the full solution set is [-1,1]. Answer: x ∈ [-1, 1]
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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