Q.

Equations of two diameters of a circle are 2x – 3y = 5 and 3x – 4y = 7. The line joining the points (–227,–4) and (–17,3) intersects the circle at only one point P(α,β). Then 17β–α is equal to __________.            [2024]


Ans.

(2)

Solving 2x – 3y = 5 and 3x – 4y = 7, we get x = 1 and y = –1

Now, equation of tangent joining the points (–227,–4) and (–17,3) is

y+4=3+4–17+227(x+227) ⇒ 3(y+4)=7(x+227)

⇒ 7x–3y+10=0

α,β be the foot of perpendicular from point (1, –1) to the line 7x – 3y + 10 = 0.

∴ α–17=β+1–3=–(7(1)–3(–1)+10)(–3)2+72=–2058=–1029

∴ α=–7029+1=–4129, β=3029–1=129

∴ 17β–α=1729+4129=5829=2.