Section 1.5 Circles Copyright © 2013 Pearson Education, Inc. All rights reserved
A circle is a set of points that are a fixed distance called the radius (r) from a point called the center (h, k) Copyright © 2013 Pearson Education, Inc. All rights reserved
Write the standard form of the equation of the circle with radius 4 and center (2, –4). Copyright © 2013 Pearson Education, Inc. All rights reserved
#9) Find the center, radius, and standard form of the equation. Practice: #9) Find the center, radius, and standard form of the equation. (1,2) (4,2) Copyright © 2013 Pearson Education, Inc. All rights reserved
Copyright © 2013 Pearson Education, Inc. All rights reserved
Copyright © 2013 Pearson Education, Inc. All rights reserved
Copyright © 2013 Pearson Education, Inc. All rights reserved
Changing from standard form to general form: (x + 2)2 + (y – 3)2 = 5 (x + 2) (x + 2) + (y – 3) (y – 3) = 5 x2 + 4x + 4 + y2 – 6y + 9 = 5 x2 + 4x + y2 – 6y + 8 = 0 Copyright © 2013 Pearson Education, Inc. All rights reserved
Copyright © 2013 Pearson Education, Inc. All rights reserved
Practice: Find the center, radius, the intercepts and graph. # 25) x2 + y2 – 2x – 4y – 4 = 0