http://www.mathcs.org/analysis/reals/cont/answers/discwp1.html"We can easily check that the limit as x approaches 3 from the right and from the left is equal to 4. Hence, the limit as x approaches 3 exists, and therefore the function has a removable discontinuity at x = 3. If we define k(3) = 4 instead of k(3) = 1 then the function in fact will be continuous on the real line."

I think from the left is eqal to 6 not to 4. Thanks.

I love your real analysis website.