Conics Hyperbola Question (1 Viewer)

Vizsla

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Here is the question.

P is a variable point on the standard hyperbola with focus S. PT is tangent at P and ST is perpendicular to PT.

Show that T lies on the circle x^2 + y^2 = a^2.

any help is appreciated
 

dan964

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I'll give you steps instead...
1. Let P represent (a sec theta, b tan theta)
2. Find dy/dx, and sub P into to find gradient of PT. Find equation of PT
3. Find equation of PS, using S as the point, and -1/m as the gradient, where m is the gradient of PT.
4. Solve equations from (2) and (3) simulateneously to find co-ordinates of T.
5. Eliminate the parameter (theta) by substitution into given result or otherwise.
 

Vizsla

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Dec 18, 2014
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Sydney
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2015
I'll give you steps instead...
1. Let P represent (a sec theta, b tan theta)
2. Find dy/dx, and sub P into to find gradient of PT. Find equation of PT
3. Find equation of PS, using S as the point, and -1/m as the gradient, where m is the gradient of PT.
4. Solve equations from (2) and (3) simulateneously to find co-ordinates of T.
5. Eliminate the parameter (theta) by substitution into given result or otherwise.
Did you go to sydney tech?
 

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