In each of the following Exercises 1 to 5, find the equation of the circle with centre (-a, -b) and radius
(x + a)² + (y + b)² = a² - b²
Explanation
This question requires applying the standard equation of a circle formula. The standard form is (x - h)² + (y - k)² = r², where (h, k) is the centre and r is the radius. Given centre (-a, -b) and radius , we substitute h = -a, k = -b, and r² = a² - b² into the formula.
Solution Steps
Step 1: Recall the standard equation of a circle: (x - h)² + (y - k)² = r²
Step 2: Identify the given values: Centre (h, k) = (-a, -b) and Radius r =
Step 3: Substitute h = -a, k = -b into the equation: (x - (-a))² + (y - (-b))² = r²
Step 4: Simplify: (x + a)² + (y + b)² = r²
Step 5: Calculate r² = ()² = a² - b²
Step 6: Final equation: (x + a)² + (y + b)² = a² - b²