Question

数轴上3点M,O,N对应的数分别为-3,0,1,点P为数轴上任意一点.

Answer 1

设M,P,N在t分钟后的坐标分别是m(t),p(t),n(t)

p(t) = -3t

m(t) = -3 - t

n(t) = 1 - 4t

P到M的距离为：|p(t)-m(t)| = |3-2t|

P到N的距离为：|p(t)-n(t)| = |t-1|

令|3-2t| = |t-1|

所以 (3-2t)^2 = (t-1)^2

化简得 3t^2 - 10t + 8 = 0

解得 t = 4/3 或 2

所以是 4/3或者2分钟之后距离相等