The equation of the circle passing through (1, 0) and (0, 1) and having smallest possible radius is : (A) `2x^2 + y^2 - 2x-y=0` (B) `x^2 + 2y^2 - x - 2y = 0` (C) `x^2 = y^2 - x - y = 0` (D) `x^2 + y^2 + x + y = 0`

The equation of the circle passing through (1/2, -1) and having pair of straight lines x^2 - y^2 + 3x + y + 2 = 0 as its two diameters is : (A) 4x^2 + 4y^2 + 12x - 4y - 15 = 0 (B) 4x^2 + 4y^2 + 15x + 4y - 12 = 0 (C) 4x^2 + 4y^2 - 4x + 8y + 5 = 0 (D) none of these

Equation of the circle passing through A(1,2), B(5,2) such that the angle subtended by AB at points the circle is pi/4 is (A) x^2+y^2-6x-8=0 (B) x^2+y^2-6x-8y+17=0 (C) x^2+y^2 -6x+8=0 (D) x^2+y^2-6x+8y-25=0

The locus of the mid-point of a chord of the circle x^2 + y^2 -2x - 2y - 23=0 , of length 8 units is : (A) x^2 + y^2 - x - y + 1 =0 (B) x^2 + y^2 - 2x - 2y - 7 = 0 (C) x^2 + y^2 - 2x - 2y + 1 = 0 (D) x^2 + y^2 + 2x + 2y + 5 = 0

Tangents OA and OB are drawn from the origin to the circle (x-1)^2 + (y-1)^2 = 1 . Then the equation of the circumcircle of the triangle OAB is : (A) x^2 + y^2 + 2x + 2y = 0 (B) x^2 + y^2 + x + y = 0 (C) x^2 + y^2 - x - y = 0 (D) x^2+ y^2 - 2x - 2y = 0

Three sides of a triangle are represented by lines whose combined equation is (2x+y-4) (xy-4x-2y+8) = 0 , then the equation of its circumcircle will be : (A) x^2 + y^2 - 2x - 4y = 0 (B) x^2 + y^2 + 2x + 4y = 0 (C) x^2 + y^2 - 2x + 4y = 0 (D) x^2 + y^2 + 2x - 4y = 0

y-1=m_1(x-3) and y - 3 = m_2(x - 1) are two family of straight lines, at right angled to each other. The locus of their point of intersection is: (A) x^2 + y^2 - 2x - 6y + 10 = 0 (B) x^2 + y^2 - 4x - 4y +6 = 0 (C) x^2 + y^2 - 2x - 6y + 6 = 0 (D) x^2 + y^2 - 4x - by - 6 = 0

The equation of the circle passing through the foci of the ellipse (x^2)/(16)+(y^2)/9=1 , and having centre at (0, 3) is (1) x^2+y^2-6y+7=0 (2) x^2+y^2-6y-5=0 (3) x^2+y^2-6y+5=0 (4) x^2+y^2-6y-7=0

The equation of a circle of radius 1 touching the circles x^2 + y^2 - 2 |x| = 0 is: (A) x^2 + y^2 + 2sqrt(3x) - 2 = 0 (B) x^2 + y^2 - 2sqrt(3)y+2=0 (C) x^2 + y^2 + 2sqrt(3) y + 2 = 0 (D) x^2 + y^2 + 2 sqrt(3) x + 2 = 0

The equation of the circle passing through the point of intersection of the circles x^2 + y^2 - 6x + 2y + 4 = 0 and x^2 + y^2 + 2x - 6y - 6=0 and having its centre on y=0 is : (A) 2x^2 + 2y^2 + 8x + 3 = 0 (B) 2x^2 + 2y^2 - 8x - 3 = 0 (C) 2x^2 + 2y^2 - 8x + 3 = 0 (D) none of these

Find the equation of circle passing through the origin and cutting the circles x^(2) + y^(2) -4x + 6y + 10 =0 and x^(2) + y^(2) + 12y + 6 =0 orthogonally.