10.7.1 write and graph equations of circles chapter 10: circles
DESCRIPTION
Why is it backwards? For a circle with radius r centered at (h, k) the equation is written: (x - h) 2 + (y - k) 2 = r 2 (1, 1) (x - 1) 2 + (y - 1) 2 = 1 h = 1 k = 1 r = 1 (1, 1) centerTRANSCRIPT
10.7.1 Write and Graph Equations of Circles
Chapter 10: Circles
Equations of a circleIn an xy plane a circle is defined by:x2 + y2 = r2
where r is the radius of the circle
(x, y)
(x, 0)
(0, y)
Why is it backwards?For a circle with radius r centered at (h, k) the
equation is written:
(x - h)2 + (y - k)2 = r2
(1, 1)(x - 1)2 + (y - 1)2 = 1
h = 1 k = 1 r = 1(1, 1) center
Write the equation in standard form
(x + 1)2 + (y - 2)2 = 4
(x – (-1))2 + (y – (2))2 = 22
(x – h)2 + (y – k)2 = r2
Identify the special line or line segment
Circle: (x + 3)2 + (y - 6)2 = 25Line:
234
xy
Diameter
Center (-3, 6)r = 5
Homeworkp. 702 1, 2, 5 – 8, 11 – 14, 16, 31 – 35, 49 – 54
report your answer in terms of do not use = 3.14 except to check answers