Question

Question. Find the equation of the circle centred at (1,-1) and
radius 2.​

Answer 1

Equation of circle with center O(a,b) and radius r :-

➝ (x-a)² + (y-b)² = r²

Now we have to find out equation of circle with center O(1,-1) and radius 2 units :-

➝ (x-1)² + (y+1)² = (2)²

➝ x²+ 1 - 2x + y² + 1 +2y= 4

➝ x² - 2x + y² +2y+2= 4

➝ x² - 2x + y² +2y+2- 4=0

➝ x² + y² - 2x +2y - 2=0

Answer :

x² + y² - 2x +2y - 2=0