有几种情况:设B(b,0) 1.OA = OB OA² = OB² 2² + 2² = (b-0)² + (0-0)² = b² b = ±2√2 B(2√2,0)或B(-2√2,0)
2.OA= AB OA² = AB² 2² + 2² = (b -2)² +(0-2)² = (b -2)² + 4 (b -2)² = 4 b -2 = ±2 b = 4或b = 0(为原点,舍去) B(4,0)
3.AB = OB
3.AB = OB OB² = AB² (b-0)² + (0-0)² = (b-2)² + (0-2)² b² = (b-2)² + 4 b = 2 B(2,0)