The function is

Graph the function

(a) \ \

Observe the graph.

increases or decreases without bound as x approaches to 3. \ \

Therefore the limit of the function does not exist as x approaches to 3.

(b). \ \

Observe the graph.

As x tends to 0, approaches to 0. \ \

.

Therefore, \ \

(a) The limit of the function does not exist as x approaches to 3.

(b).