Recall that
if the right hand and left hand limits at x = c coincide, then we say that the common
value is the limit of the function at x = c Hence we may also rephrase  the definition of
continuity as follows: a function is continuous at x = c if the function is defined at
x = c and if the value of the function at x = c equals the limit of the function at
x = c If f is not continuous at c, we say f is discontinuous at c and c is called a point
of discontinuity of f Fig 5