Answer :
Answer:
[tex]\dfrac{y^2}{225} -\dfrac{x^2}{216}=1[/tex]
Step-by-step explanation:
For a hyperbolic mirror the two foci are 42 cm apart.
The distance between the foci = 2c.
Therefore:
- 2c=42
- c=21
The distance of the vertex from one focus = 6 cm
The distance of the vertex from the other focus = 36 cm
2a=36-6=30
- a=15
Now:
[tex]c^2=a^2+b^2\\21^2=15^2+b^2\\b^2=21^2-15^2\\b^2=216\\b=6\sqrt{6}[/tex]
If the transverse axis lies on the y-axis, and the hyperbola is centered at the origin. Then the hyperbola has an equation of the form:
[tex]\dfrac{y^2}{a^2} -\dfrac{x^2}{b^2}=1[/tex]
Therefore, the equation of the hyperbola is:
[tex]\dfrac{y^2}{225} -\dfrac{x^2}{216}=1[/tex]