因为：-½≤x≤1
所以 √(x - 1)² + | x - 1| + √(4x² + 4x + 1)
= 1 - x + 1 - x + √(2x + 1)²
= 2 - 2x + (2x + 1)
= 2 - 2x + 2x + 1
= 3