Question

What is the equation of the circle with a center at `(-3 ,-1 )` and a radius of `1`?

Answer 1

`(x+3)^2+(y+1)^2=1`

Explanation:

The standard form of a circle with a center at `(h,k)` and a radius `r` is

`(x-h)^2+(y-k)^2=r^2`

Since the center is `(-3,-1)` and the radius is `1`, we know that

`{(h=-3),(k=-1),(r=1):}`

Thus, the equation of the circle is

`(x-(-3))^2+(y-(-1))^2=1^2`

This simplifies to be

`(x+3)^2+(y+1)^2=1`