Question

In the equation y^2=4px find the value of p under each of the follow conditions;
a) the distance from the vertex to the focus is 3

b) the focus is the point (-5, 0)

Answer 1

for part b) i think p=-5 am i correct?

Answer 2

@amistre64

Answer 3

i never really worked with that form, what does p represent?

Answer 4

the focus point i think
like example y^2=12x
so 4p=12
p=12/4
p=3

the focus (3,0)
directrix x=-3

Answer 5

spose f(0,p) and d: y=-p

(x-0)^2 + (y-p)^2 = (x-x)^2 + (y+p)^2

x^2 + y^2 -2py +p^2 = y^2 +2py + p^2

x^2 -2py = 2py

x^2 = 4p y

ok, p represents the distance from vertex to focus/directrix

Answer 6

find the value of p, well if the distance given is 3 ... then p=3 :)

and -5 seems fine for the other one yes

Answer 7

ok so p is the distance

Answer 8

part a can have 2 results. 3 and -3 since distance is not dependant on direction

Answer 9

the equation, let p represent the distance AND direction from vertex to focus

Answer 10

ok would u say that the latus rectum when divided by 2 gives the focal radius?

Answer 11

the latrec being the line thru the focus roght?

Answer 12

yea