Observe the graph.

We can observe from the graph that exists for all values of except at  and .

As tends to from the left hand side, tends to .

As tends to from the right hand side, tends to .

Since the left hand limit and right hand limit are equal, limit exist at .

We can observe from the graph that exists for all values of except at  and .

As tends to from the left hand side, tends to .

As tends to from the right hand side, tends to .

Since the left hand limit and right hand limit are undefined, limit does not exist at .

exists for all values of except at .

As tends to from the left hand side, tends to .

As tends to from the right hand side, tends to .

Since the left hand limit and right hand limit are not equal, limit does not exist at .

exists for all values of except at .

exists for all values of except at and .