The function is , where is the viewing angle and is the distance between the person and the screen.

(a)

The function is .

Substitute in the function.

.

Substitute in the function.

.

Substitute in the function.

.

(b)

The first row is from the screen.

Distance between each row is .

To find which row results in the largest viewing angle, make the below table.

Rows	Distance between each row and screen	\ viewing angle \ \
	\ \

Observe the above table :

Row results largest viewing angle.

(c)

The function is .

Draw a coordinate plane.

Plot the points obtained in the above table.

Connect those points with a smooth curve.

Graph :

Observe the above angle :

From above table and graph.

The largest viewing angle is .

(a)

, , .

(b)

Row results largest viewing angle.

(c)

Graph :

The largest viewing angle is .