$\"\"$

\

The function is $\"\"$ .

\

(a).

\

Find the value of $\"\"$ .

\

$\"\"$

\

$\"\"$

\

$\"\"$

\

$\"\"$

\

$\"\"$

\

Therefore, $\"\"$ .

\

As the time $\"\"$ tends to $\"\"$ , the value of the velocity $\"\"$ is constant.

\

$\"\"$

\

(b).

\

Use l $\"\"$ Hospital rule to find $\"\"$ .

\

$\"\"$ .

\

Evaluate of the limit.

\

$\"\"$

\

$\"\"$

\

$\"\"$

\

$\"\"$

\

L $\"\"$ Hospital $\"\"$ s Rule :

\

If the value of limit is indeterminate form of type $\"\"$ or $\"\"$ , then

\

$\"\"$

\

$\"\"$

\

Since $\"\"$ use L $\"\"$ Hospital $\"\"$ s rule.

\

$\"\"$

\

$\"\"$

\

$\"\"$

\

$\"\"$

\

$\"\"$

\

Therefore, $\"\"$ .

\

$\"\"$

\

(a) $\"\"$ .

\

As the time $\"\"$ tends to $\"\"$ , the value of the velocity $\"\"$ is constant.

\

(b) $\"\"$ .