# Circle Equation

1. Sep 24, 2009

### DrMath

1. The problem statement, all variables and given/known data

is:
>= 1

valid for a circle equation?
See attached?

2. Relevant equations

reference attached

3. The attempt at a solution

reference attached

#### Attached Files:

• ###### Circle Eqn.jpg
File size:
12.1 KB
Views:
62
2. Sep 24, 2009

### rock.freak667

if you mean x2+y2≥1 , then yes it is a 'circle' in essence but the points (x,y) that satisfy the inequality do not lie on the circle itself like if if it was x2+y2=1

3. Sep 26, 2009

### tiny-tim

Hi DrMath!

(have a ≥ and try using the X2 and X2 tags just above the Reply box )

Your picture says |z - 2j| ≥ 1 …

in other words, the magnitude of the "vector" from 2j to z has length ≥ 1 …

so z is the exterior (and boundary) of the circle of length 1 and centre at 2j

(btw, it's easier to use "vectors" rather than coordinates for as problem like this )

4. Sep 26, 2009

### DrMath

Thanks tiny-tim
oh.. how to become a Homework Helper here?

5. Sep 27, 2009

### tiny-tim

just help people with their homework!