conics (1 Viewer)

bob fossil

Member
Joined
Oct 22, 2009
Messages
225
Location
newcastle
Gender
Male
HSC
2010
please help i think im stuck about half way.

P is the point (x1,y1) on the ellipse x^2/a^2+y^2/b^2=1. The normal at P meets the x axis at G. N is the foot of the perpendicular from p to the x axis.

Prove OG=e^ON


So far i have found the equation of the tangent
Let it = 0 for G
G=(a^2/x1,0)

Now i am stuck all i have is N=(x1,0)
 

Trebla

Administrator
Administrator
Joined
Feb 16, 2005
Messages
8,164
Gender
Male
HSC
2006
please help i think im stuck about half way.

P is the point (x1,y1) on the ellipse x^2/a^2+y^2/b^2=1. The normal at P meets the x axis at G. N is the foot of the perpendicular from p to the x axis.

Prove OG=e^ON


So far i have found the equation of the tangent
Let it = 0 for G
G=(a^2/x1,0)

Now i am stuck all i have is N=(x1,0)
Couple of things:
- Not quite clear what the thing is to prove "e^ON"??
- The normal at P meets the x-axis at G, NOT the tangent (you need the equation of the normal)
 

bob fossil

Member
Joined
Oct 22, 2009
Messages
225
Location
newcastle
Gender
Male
HSC
2010
ok i worked it out.


now im fully stuck on prove SG=e.SP


does SG=ea-x1e^2
 
Last edited:

Users Who Are Viewing This Thread (Users: 0, Guests: 1)

Top