Question

Find the equation of the circle with a center at (2,-1) and a radius of square root of 12

Answer 1

`x^(2)`+
`y^(2)` -4x+2y-7=0

Explanation:

Given that, center at (2,-1)

let a = 2, b = -1

radius, r =
`√(12)`

As we know the equation circle is,
`(x-a) ^(2)`+
`(y-b) ^(2)` =
`r^(2)` when radius and center point is given.

By this formula , we can get,

`(x-2) ^(2)`+
`(y-(-1)) ^(2)` =
`√(12) ^(2)`

`x^(2)` -4x +4 +
`y^(2)` + 2y + 1 = 12

`x^(2)`+
`y^(2)` -4x+2y-7=0

This is the answer.