Question

A circle has radius 4 unit and its center lies on x + y = 0 and it passes through (1, 1) . Find its equation.​

Answer 1

Step-by-step explanation:

(x−h)2+(y−k)2=r2

Here (h,k)→ centre

Equation of line through centre 

k=h−1−−−−(1)

& (x,y) point on circle

So, given (x,y)=(7,3)

So, (7−h)2+(3−h+1)2=32

Using eqn (1)

We get,

28+h2−11h=0

h=7 oR 4

k=6 oR 3

Equation of circle corresponding (7,6)

x2+y2−14x−12y+76=0

Equation of circle corresponding (4,3)

x2+y2−8x−6y+16=0