$\"\"$

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The function is $\"\"$ and the point is $\"\"$ .

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

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$\"\"$

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Substitute the point $\"\"$ in above equation.

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$\"\"$

\

$\"\"$ .

\

$\"\"$

\

The function is $\"\"$ .

\

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

\

$\"\"$

\

Substitute the point $\"\"$ in above equation.

\

$\"\"$

\

$\"\"$ . $\"\"$

\

The function is $\"\"$ .

\

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

\

$\"\"$

\

Substitute the point $\"\"$ in above equation.

\

$\"\"$

\

$\"\"$ .

\

$\"\"$

\

$\"\"$ .

\

$\"\"$ .

\

$\"\"$ .