312-155 =157 (m)

Xiaoming's home to Xiaohong's home 157 meters.

(2) Xiaohong's family and Xiaoming's family are on both sides of the school:

3 12+ 155=467 (m)

It is 467 meters from Xiaoming's home to Xiaohong's.

1. Distance generally refers to the line segment between two points. In mathematics, distance is a scalar, has no direction and cannot be negative. At the same time, distance is one of the most basic concepts in functional analysis. Intuitively, if the sequence is regarded as a series of points on the real number axis, then the distance between any two points is equal to the absolute value of the difference between the two points.

2. There are many different kinds of distances in mathematics, which are often used in mathematics research such as geometry and advanced algebra. Various distances are widely used in mathematical modeling and computer learning. For example, an evaluation function during a * search. For example, in machine learning, it is often necessary to estimate the similarity measure between different samples when classifying, and the usual method is to calculate the distance between samples. What kind of method is used to calculate the distance is very particular, even related to the correctness of classification.

3. Euclidean distance Euclidean distance is the most understandable distance calculation method, which comes from the distance formula between two points in Euclidean geometry.

Euclidean distance between two points a (x 1, y1) a (x 1, y 1)b(x2, y2)b(x2, y2) on the two-dimensional plane:

(2) two n-dimensional vectors a(x 1 1, x 12, x 1n)a(x 1 1, x/.

4. Manhattan distance You can guess the calculation method of this distance from the name. Imagine that you have to drive from one intersection in Manhattan to another. Is the driving distance between two points a straight line? Obviously not, unless you can get through the building. The actual driving distance is this "Manhattan distance". This is also the origin of the name Manhattan distance, also known as the city block distance.

5. Have you ever played Chebyshev distance chess? The king can move to any of the eight adjacent squares in one step. So how many steps does the king need to take to get from the grid (x 1, y 1) to the grid (x2, y2)? Try to walk by yourself. You will find that the minimum number of steps is always max( | x2-x 1 |, | y2-y 1 |). There is a similar distance measurement method called Chebyshev distance.