x1 + x2 = -a
x1 * x2 = a - 2
(x1 - x2)²
= (x1 + x2)² - 4x1 * x2
= a² - 4(a - 2)
= a² - 4a + 4 + 4
= (a - 2)² + 4
所以 (x1 - x2)²的最小值是 4
d
= |x1 - x2|
= √(x1 - x2)²
= √4
= 2
所以图像与 x 轴两交点间的最小距离是 2
x1 + x2 = -a
x1 * x2 = a - 2
(x1 - x2)²
= (x1 + x2)² - 4x1 * x2
= a² - 4(a - 2)
= a² - 4a + 4 + 4
= (a - 2)² + 4
所以 (x1 - x2)²的最小值是 4
d
= |x1 - x2|
= √(x1 - x2)²
= √4
= 2
所以图像与 x 轴两交点间的最小距离是 2