Let A1 2 x 1 y 1 B-2 2 x 2 y 2 To find. They only indicate that there is a first point and a second point. That is that you have two points.
Now learn how to derive the distance formula in geometry.
Find the distance between the two points A1 2 and B-2 2. Scrub the values of A and B coordinates to see how they connect to terms in the final distance formula. Math 20C Multivariable Calculus Lecture 2 1 Slide 1 y1z1 and P2x2y2z2 is given by jP1P2j x2 x12 y2 y12 z2 z12 12. That is that you have two points.