Given, The circle's equation is x2+y2+2x+2y+1=0 Rewrite by completing squares: (x+1)2+(y+1)2=1 ∴ center =(−1,−1), radius r=1 For a square inscribed in this circle with sides parallel to the axes, its diagonal equals the circle's diameter =2. If the square has side length a, then a√2=2⇒a=√2. Each vertex lies a half-side =
a
2
=
1
√2
from the center along both axes. Since the center is (−1,−1), the four vertices are (−1±