The set of all points of continuous of fofof, where `f(x) = sgn(x)` is

The set of all points, where the function f (x) = x/(1+|x|) is differentiable, is

If f(x) = sgn (x) and g (x) = (1-x^2) ,then the number of points of discontinuity of function f (g (x)) is -

Let f(x)=g(x)sgn(x^(3)+6x^(2)+11x+6) where sgn denotes signum function and f(x)=ax^(3)+x^(2)+x+1, then minimum number of points of discontinuity of the function f(x) is

The set of all points where f(x)=2x|x| is differentiable