The equation of the ellipse is and the point is
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Slope of the tangent is the derivative of the curve.
\Consider .
Differentiate on each side with respect to .
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Assume that the ellipse has the tangent at the point .
Slope of the tangent at .
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Find the equation of the tangent at .
Point-slope form of line equation is .
Substitute and
in point - slope form.
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The above line passes through the point .
So it will satisfy the above tangent line equation.
\The point lies on ellipse.
Therefore, .
Substitute above result in .
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Substitute in
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and
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Substitute values of in
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If , then
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If , then
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Thus, the tangent points are and
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Find the equation of the tangent line at .
Slope of the tangent line at :
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Point - slope form of line equation is .
Substitute and
in point - slope form.
Equation of the tangent to ellipse at is
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Find the equation of the tangent line at .
Slope of the tangent line at :
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Tangent at :
Point-slope form of line equation is .
Substitute and
in point - slope form.
Equation of the tangent to ellipse at is
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Tangent lines to ellipse are and
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