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

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

<p>The square of distance AB between two points is </p>

<p>AB²=(x1-x2)²+(y1-y2)²</p>

<p>After calculating the distance AB. </p>

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

<p>AB²=(1-4)²+(2-6)²=25</p>

<p>AB=√25=5</p>

<p>It can also be calculated directly. :</p>

<p>AB=√[(1-4)²+(2-6)²]=√25=5</p>