It is often used to find the distance in function graphics, and then to find the coordinates of points by distance.

The coordinates of points A and B are known to be A(x1,y1)，B(x2,y2)

The square of distance AB between two points is

AB²=(x1-x2)²+(y1-y2)²

After calculating the distance AB.

For example, the coordinates of points A and B are known to be A(1,2)，B(4,6)

AB²=(1-4)²+(2-6)²=25

AB=√25=5

It can also be calculated directly. :

AB=√[(1-4)²+(2-6)²]=√25=5

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