Let us construct the function .
f ( x ) = x 2 , whenever x ≥ x 2 , i . e , whenever x lies between 0 to 1 .
= 2x - x 2 , whenever x ≤ x 2 , i . e , whenever x lies between - 1 to 0 .
Clearly , x = 0 is the only critical point .
But , both the R . H . L and L . H . L have the same value as the functional value at x = 0 ,
i.e , both are zero at x = 0 .
So the function has zero number of discontinuities .