Q.

Let P(x0,y0) be the point on the hyperbola 3x2-4y2=36, which is nearest to the line 3x+2y=1. Then 2 (y0-x0) is equal to        [2023]

1 - 9  
2 3  
3 9  
4 - 3  

Ans.

(1)

We have, 3x2-4y2=36

The slope of 3x+2y=1 is m=-32 

The point of hyperbola is (12secθ, 3tanθ).

The equation of normal is 12 xcosθ+3ycotθ=21

⇒Slope =-12cosθ3cotθ

According to questions, (-32)(-12cosθ3cotθ)=-1

⇒3sinθ=-1  ⇒ sinθ=-13 ⇒ cosθ=23

∴ (x0,y0)≡(62,-32)  ∴ 2 (y0-x0)=-9