The limit of the function is .

The squeeze theorem :

If  when  is near to  and

 then .

Use the squeeze theorem:

Find the function  lesser than  and a function  greater than , such that  and  are approaches to .

The range of cosine function is .

 .

Multiply  throughout the equation.

By the squeeze theorem ,  and .

, then .

 .

Graph :

Graph the functions on the same plane.

(1) Draw the coordinate plane.

(2) Graph the function .

(3) Graph the function .

(4) Graph the function .

.