Question

Find the length of transverse axis, length of conjugate axis, the eccentricity, the co-ordinates of foci, equations of directrices and the length of latus rectum of the hyperbola:

x² – y² = 16

Answer 1

Given equation of the hyperbola is x² – y² = 16

∴ `x^2/16 - y^2/16` = 1

Comparing this equation with `x^2/"a"^2 - y^2/"b"^2` = 1, we get

a² = 16 and b² = 16

∴ a = 4 and b = 4

Length of transverse axis = 2a = 2(4) = 8

Length of conjugate axis = 2b = 2(4) = 8

We know that

e =`sqrt("a"^2 + "b"^2)/"a"`

= `sqrt(16 + 16)/4`

= `sqrt(32)/4`

= `(4sqrt(2))/4`

= `sqrt(2)`

Co-ordinates of foci are S(ae, 0) and S'(– ae, 0),

i.e., `"S"(4sqrt(2), 0)` and `"S""'"(-4 sqrt(2), 0)`

Equations of the directrices are x = `± "a"/"e"`.

∴ x = `± 4/sqrt(2)`

∴ x = `±2sqrt(2)`

Length of latus rectum = `(2"b"^2)/"a"`

= `(2(16))/4`

= 8.