Step 1:
\Observe the graph of the function:
\
We can observe from the graph that
exists.
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,
\
Step 1:
\Observe the graph of the function:
\
We can observe from the graph that
does not exists.
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,
\
does not exist. \ \
Since the left hand limit and right hand limit are not equal,
\Limit does not exist at
.
does not exist.
(c) 
We can observe from the graph that
exists.
The solid dot indicates that value of the function exist at
.
.
(d)
We can observe from the graph that
does not exists.
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
.
does not exist.
(e) 
We can observe from the graph that
does not exists.
The hollow dot indicates that value of the function does not exist at
.
is undefined.
(f)
We can observe from the graph that
exists.
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
.
.
(g) 
We can observe from the graph that
exists.
The solid dot indicates that value of the function exist at
.
.
(h) 
As
tends to 4 from the left hand side,
tends to
.
As
tends to 4 from the right hand side,
tends to
.
Since the left hand limit and right hand limit are undefined,
\Limit does not exist at
.
does not exist.
(a)
is undefined.
(b)
does not exist.
(c)
.
(d)
does not exist.
(e)
is undefined.
(f)
.
(g)
.
(h)
does not exist.