Find the equation of the hyperbola whose
focus is at (4, 2), centre at (6, 2) and e = 2.
Given: Foci is (4, 2), e = 2 and center at (6, 2)
To find: equation of the hyperbola
Formula used:
The standard form of the equation of the hyperbola is,
Center is the mid-point of two vertices
The distance between two vertices is 2a
The distance between the foci and vertex is ae – a and b2 = a2(e2 – 1)
The distance between two points (m, n) and (a, b) is given by
Mid-point theorem:
Mid-point of two points (m, n) and (a, b) is given by
Therefore
Let one of the two foci is (m, n) and the other one is (4, 2)
Since, Centre(6, 2)
Foci are (4, 2) and (8, 2)
The distance between the foci is 2ae and Foci are (4, 2) and (8, 2)
⇒ a2 = 1
b2 = a2(e2 – 1)
⇒ b2 = 4 – 1
⇒ b2 = 3
The equation of hyperbola:
⇒ 3(x2 + 36 – 12x) – (y2 + 4 – 4y) = 3
⇒ 3x2 + 108 – 36x – y2 – 4 + 4y – 3 = 0
⇒ 3x2 – y2 – 36x + 4y + 101 = 0
Hence, required equation of hyperbola is 3x2 – y2 – 36x + 4y + 101 = 0