The limit of the function is .

The squeeze theorem :

If when is near to and

then .

Use the squeeze theorem, so find the function lesser than and a function greater than ,

such that and are approaches to .

The range of cosine function is .

So .

Multiply  throughout the equation.

By the squeeze theorem , and .

, then .

Therefore .

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 .

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