$\"\"$

Find the derivative of $\"\"$ .

Rewrite the above expression $\"\"$ .

Apply derivative on each side with respect to $\"\"$ .

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Chain rule of derivative: $\"\"$ .

Derivative of inverse cosine function : $\"\"$ .

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The slope of the tangent at the point $\"\"$ .

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Slope point form of the line equation is $\"\"$ .

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$\"\"$ .