Find the equation of the circle with centre : `(-a , - b)`and radius `sqrt(a^2-b^2)`.

Explanation

To find the equation of the circle with center \((-a, -b)\) and radius \(\sqrt{a^2 - b^2}\), we will use the standard form of the equation of a circle.

### Step-by-Step Solution:

1. **Identify the center and radius**:
- The center of the circle is given as \((-a, -b)\), which means \(h = -a\) and \(k = -b\).
- The radius is given as \(r = \sqrt{a^2 - b^2}\).

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