parametrics and focal chord (1 Viewer)

sssona09

Member
Joined
Oct 2, 2015
Messages
90
Gender
Female
HSC
2018
pls help rip
P(2at,at^2) is a point on the parabola x^2=4ay. S is the focus, T is the foot of the perpendicular frpm P to the directrix, and A is the point where the tangent at P meets the y aixs.
(i) write down the coordinates of T
(ii) show that A is the point (0, -at^2)
(iii) what is point S
 

pikachu975

Premium Member
Joined
May 31, 2015
Messages
2,739
Location
NSW
Gender
Male
HSC
2017
pls help rip
P(2at,at^2) is a point on the parabola x^2=4ay. S is the focus, T is the foot of the perpendicular frpm P to the directrix, and A is the point where the tangent at P meets the y aixs.
(i) write down the coordinates of T
(ii) show that A is the point (0, -at^2)
(iii) what is point S
I'll just give hints

i) Use formula sheet for the normal equation as it says perpendicular at P and sub y = -a as that is the directrix equation

ii) Use tangent equation on formula sheet and sub x = 0

iii) (0, a) as it is the focus
 

sssona09

Member
Joined
Oct 2, 2015
Messages
90
Gender
Female
HSC
2018
I'll just give hints

i) Use formula sheet for the normal equation as it says perpendicular at P and sub y = -a as that is the directrix equation

ii) Use tangent equation on formula sheet and sub x = 0

iii) (0, a) as it is the focus
ohh thank youuuu pikachu
 

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

Top