$\"\"$

The equation is $\"\"$ .

The width of the panel is $\"\"$ .

Observe the diagram.

The length of two periods is $\"\"$ .

The length of one period is $\"\"$ .

$\"\"$

Differentiate with respect to $\"\"$ .

$\"\"$

Arc length length formula : $\"\"$ .

The arc length of the sine wave is the width of the panel $\"\"$ , where $\"\"$ is $\"\"$ .

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Using calculator, the value of above integral is $\"\"$ .

Therefore, the width of the panel $\"\"$ is $\"\"$ . $\"\"$

The width of the panel is $\"\"$ .