If the circle x2 + y2 = a intersects the hyperbola xy = c2 in four points (xi, yi), for i = 1, 2, 3 and 4, then y1 + y2 + y3 + y4 equals
0
c
a
c4
The centre and radius of the sphere x2 + y2 + z2 + 3x - 4z + 1 = 0 are
C.
The given equation of sphere is
x2 + y2 + z2 + 3x - 4z + 1 = 0
On comparing this equation with general equation of sphere x2 + y2 + z2 + 2ux + 2vy + 2wz + d = 0,
we get
Let A and B are two fixed points in a plane, then locus of another point Con the same plane such that CA + CB = constant, (> AB) is
circle
ellipse
parabola
hyperbola