$\"\"$

\

The width in millimeters of an animals pupil is $\"\"$ .

\

Where $\"\"$ is the illuminance of the light measured in lux.

\

(a)

\

Find the value of the limit when the light is at minimum illuminance.

\

When the light is at minimum illuminance, the limit expression is $\"\"$ .

\

$\"\"$

\

$\"\"$

\

$\"\"$

\

$\"\"$

\

$\"\"$

\

Therefore, the width of the animals pupil is $\"\"$ millimeters when the light is at minimum illuminance.

\

$\"\"$

\

(b)

\

Find the value of the limit when the light is at maximum illuminance.

\

When the light is at maximum illuminance, the limt expression is $\"\"$ .

\

$\"\"$

\

$\"\"$

\

If the value of $\"\"$ then $\"\"$ .

\

$\"\"$

\

$\"\"$

\

$\"\"$

\

$\"\"$

\

Therefore, the width of the animals pupil is $\"\"$ millimeters when the light is at maximum illuminance.

\

$\"\"$

\

(a) The width of the animals pupil is $\"\"$ millimeters when the light is at minimum illuminance.

\

(b) The width of the animals pupil is $\"\"$ millimeters when the light is at maximum illuminance.