Given that x 2 36 + y 2 4 = 1 \dfrac{{x}^{2}}{36} + \dfrac{{y}^{2}}{4} = 1 36 x 2 + 4 y 2 = 1
Observe that \left(3\sqrt{3}, 1\right)l i e s o n t h e g i v e n e l l i p s e . < / p > < p > E q u a t i o n o f t a n g e n t t o t h e e l l i p s e a t t h e g i v e n p o i n t i s lies on the given ellipse.</p><p>Equation of tangent to the ellipse at the given point is l i eso n t h e g i v e n e ll i p se . < / p >< p > Eq u a t i o n o f t an g e n tt o t h ee ll i p se a tt h e g i v e n p o in t i s T: \dfrac{3\sqrt{3}x}{36} + \dfrac{y}{4} = 1< / p > < p > </p><p> < / p >< p > ⇒ \dfrac{\sqrt{3}x}{12} + \dfrac{y}{4} = 1< / p > < p > E q u a t i o n o f n o r m a l p a s s i n g t h r o u g h s a m e p o i n t w i l l b e </p><p>Equation of normal passing through same point will be < / p >< p > Eq u a t i o n o f n or ma lp a ss in g t h ro ug h s am e p o in tw i ll b e N: \dfrac{x - 3\sqrt{3}}{\dfrac{3\sqrt{3}}{36}} = \dfrac{y - 1}{\dfrac{1}{4}}< / p > < p > </p><p> < / p >< p > ⇒ \dfrac{12x - 36\sqrt{3}}{\sqrt{3}} = 4y - 4< / p > < p > </p><p> < / p >< p > ⇒ 3x - 9\sqrt{3} = \sqrt{3}y - \sqrt{3}< / p > < p > </p><p> < / p >< p > ⇒ 3x - \sqrt{3}y = 8\sqrt{3}< / p > < p > N o w t a n g e n t a n d n o r m a l i n t e r s e c t s t h e </p><p>Now tangent and normal intersects the < / p >< p > N o wt an g e n t an d n or ma l in t ersec t s t h e y -a x i s a t axis at a x i s a t Aa n d and an d Br e s p e c t i v e l y . < / p > < p > respectively.</p><p> res p ec t i v e l y . < / p >< p > A\left(0, 4\right)B\left(0, - 8\right)< / p > < p > E q u a t i o n o f c i r c l e w i t h </p><p>Equation of circle with < / p >< p > Eq u a t i o n o f c i rc l e w i t h ABa s d i a m e t e r w i l l b e < / p > < p > ( x − x 1 ) ( x − x 2 ) + ( y − y 1 ) ( y − y 2 ) = 0 as diameter will be</p><p>\left(x - {x}_{1}\right)\left(x - {x}_{2}\right) + \left(y - {y}_{1}\right)\left(y - {y}_{2}\right) = 0 a s d iam e t er w i ll b e < / p >< p > ( x − x 1 ) ( x − x 2 ) + ( y − y 1 ) ( y − y 2 ) = 0
⇒ x 2 + ( y − 4 ) ( y + 8 ) = 0 \text{⇒}{x}^{2} + ( y - 4 ) ( y + 8 ) = 0 ⇒ x 2 + ( y − 4 ) ( y + 8 ) = 0
Line x = 2 5 x = 2\sqrt{5} x = 2 5 intersects the circle.
⇒ 20 + y 2 + 4 y − 32 = 0 ⇒ 20 + {y}^{2} + 4y - 32 = 0 ⇒ 20 + y 2 + 4 y − 32 = 0
⇒ y 2 + 4 y − 12 = 0 ⇒ {y}^{2} + 4y - 12 = 0 ⇒ y 2 + 4 y − 12 = 0
⇒ ( y + 6 ) ( y − 2 ) = 0 ⇒ ( y + 6 ) ( y - 2 ) = 0 ⇒ ( y + 6 ) ( y − 2 ) = 0
Hence P ( 2 5 , − 6 ) Q ( 2 5 , 2 ) P ( 2\sqrt{5}, - 6 ) Q ( 2\sqrt{5}, 2 ) P ( 2 5 , − 6 ) Q ( 2 5 , 2 )
Now let us find the equation of tangents to the circle at P , Q P, Q P , Q .
⇒ T : x x 1 + y y 1 + 2 y + 2 y 1 − 32 = 0 ⇒ T: x{x}_{1} + y{y}_{1} + 2y + 2{y}_{1} - 32 = 0 ⇒ T : x x 1 + y y 1 + 2 y + 2 y 1 − 32 = 0
⇒ T 1 : 2 5 x − 6 y + 2 y − 12 − 32 = 0 ⇒ {T}_{1}: 2\sqrt{5}x - 6y + 2y - 12 - 32 = 0 ⇒ T 1 : 2 5 x − 6 y + 2 y − 12 − 32 = 0
⇒ 2 5 x − 4 y = 44 ⇒ 2\sqrt{5}x - 4y = 44 ⇒ 2 5 x − 4 y = 44
⇒ T 1 : 5 x − 2 y = 22........ ( i ) ⇒ {T}_{1}: \sqrt{5}x - 2y = 22 . . . . . . . . \left(i\right) ⇒ T 1 : 5 x − 2 y = 22........ ( i )
⇒ T 2 : 2 5 x + 2 y + 2 y + 4 − 32 = 0 ⇒ {T}_{2}: 2\sqrt{5}x + 2y + 2y + 4 - 32 = 0 ⇒ T 2 : 2 5 x + 2 y + 2 y + 4 − 32 = 0
⇒ 2 5 x + 4 y = 28 ⇒ 2\sqrt{5}x + 4y = 28 ⇒ 2 5 x + 4 y = 28
⇒ T 2 : 5 x + 2 y = 14......... ( i i ) ⇒ {T}_{2}: \sqrt{5}x + 2y = 14 . . . . . . . . . \left(ii\right) ⇒ T 2 : 5 x + 2 y = 14......... ( ii )
From \left(i\right)a n d ( i i ) and \left(ii\right) an d ( ii )
α = 18 5 β = − 2 \alpha = \dfrac{18}{\sqrt{5}}\beta = - 2 α = 5 18 β = − 2
⇒ α 2 − β 2 = 304 5 ⇒ {\alpha}^{2} - {\beta}^{2} = \dfrac{304}{5} ⇒ α 2 − β 2 = 5 304
Hence this is the required option.