Problems

In Problems 1-6, find the distance between the points P and Q.

1	P(2, 9), Q(-1,13)
2	P(1, -2), Q(2, 10)
3	P(0, 0), Q(-2,-3)
4	P(-1, -1), Q(4,4)
5	P(6, 1), Q(-7, 1)
6	P(5, 10), Q(9, 10)

Sketch the circles given in Problems 7-12.

7	x2 + y2 = 4
8	x2 + y2 = ¼
9	(x - 1)2 + (y + 2)2 = 1
10	(x + 2)2 + (y + 3)2 = 9
11	(x - 1)2 + (y - 1)2 = 2
12	(x + 3)2 + (y - 4)2 = 25

13	Find the equation of the circle of radius 2 with center at (3, 0).
14	Find the equation of the circle of radius √3 with center at (-1, -2).
15	There are two circles of radius 2 that have centers on the line x = 1 and pass through the origin. Find their equations.
16	Find the equation of the circle that passes through the three points (0, 0), (0, 1), (2, 0).
17	Find the equation of the circle one of whose diameters is the line segment from (-1,0) to (5, 8).