Let a relation R be defined on set of all real numbers by a R b if and only if 1 + ab > 0. Then, R is
reflexive, transitive but not symmetric
reflexive, symmetric but not transitive
symmetric, transitive but not reflexive
an equivalence relation
The smallest circle with centre on y-axis and passing through the point (7, 3) has radius
7
3
4
B.
7
Let the centre of circle on y-axis be (0, k).
The normal to the curve x = , y = at any point is such that
it makes a constant angle with x-axis
it passes through origin
it is at a constant distance from origin
None of the above
Differential equation of those circles which passes through origin and their centres lie on y-axis will be