$\"\"$

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The function is $\"\"$ .

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The general form of cosine function is $\"\"$ .

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Where $\"\"$ is amplitude and period $\"\"$ .

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Compare the function with general form of cosine function.

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Here amplitude is $\"\"$ .

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The period is $\"\"$ .

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The amplitude of the function is $\"\"$ , so the graph $\"\"$ is in between $\"\"$ and $\"\"$ on $\"\"$ -axis.

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The negative sign indicates that the function flips about $\"\"$ -axis.

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The period of the function is $\"\"$ .

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Therefore, the cosine wave starts from $\"\"$ and completes one cycle at $\"\"$ .

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$\"\"$

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The function is $\"\"$ .

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The interval of the function is $\"\"$ .

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Divide the interval $\"\"$ into eight subintervals, each of length $\"\"$ .

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The points are $\"\"$ , $\"\"$ , $\"\"$ , $\"\"$ , $\"\"$ , $\"\"$ , $\"\"$ , $\"\"$ .

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The end points of the subintervals are $\"\"$ .

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Locate the key points:

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$\"\"$ .

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$\"\"$

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Graph the function $\"\"$ .

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Graph:

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Draw a coordinate plane.

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Plot the points on the graph.

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Connect the points using smooth curve. \ \

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$\"graph$

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Observe the graph:

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The domain of the function is $\"\"$ .

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The range of the function is $\"\"$ .

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$\"\"$

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Graph of the function $\"\"$ is

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$\"graph$ \ \

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The domain of the function is $\"\"$ .

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The range of the function is $\"\"$ .