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11.2 the Parabola. Its says Conic sections:
suppose PQ is a focal chord of the parabola y=x^2 and that the coordinates of P are (2,4)
a)find coordinate of Q
b)find coordinates of M, the midpoint of PQ.
c) A perpendicular is drawn from M to the y axis, meeting the y axis at S. Also, a line perpendicular to the focal chord is drawn through M, meeting the yaxis and T.
Find ST, and verify its equal to onehalf the focal width of the parabola.
 one year ago
 one year ago
11.2 the Parabola. Its says Conic sections: suppose PQ is a focal chord of the parabola y=x^2 and that the coordinates of P are (2,4) a)find coordinate of Q b)find coordinates of M, the midpoint of PQ. c) A perpendicular is drawn from M to the y axis, meeting the y axis at S. Also, a line perpendicular to the focal chord is drawn through M, meeting the yaxis and T. Find ST, and verify its equal to onehalf the focal width of the parabola.
 one year ago
 one year ago

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lilsis76Best ResponseYou've already chosen the best response.0
dw:1352584620353:dw
 one year ago

lilsis76Best ResponseYou've already chosen the best response.0
dw:1352584696851:dw
 one year ago

lilsis76Best ResponseYou've already chosen the best response.0
whats a focal chord? I was givin this homework problem and instructor confused me on all the different positions
 one year ago

AperogalicsBest ResponseYou've already chosen the best response.0
Any chord to y2 = 4ax which passes through the focus is called a focal chord of the parabola y2 = 4ax.
 one year ago

AperogalicsBest ResponseYou've already chosen the best response.0
@lilsis76 tell me the focus of ur parabola?????:)
 one year ago

lilsis76Best ResponseYou've already chosen the best response.0
well, it didnt give me a focus it just gave me the P at (2,4)
 one year ago

lilsis76Best ResponseYou've already chosen the best response.0
it also says the parabola is y=x^2 so...um the p, 1/4
 one year ago

AperogalicsBest ResponseYou've already chosen the best response.0
@lilsis76 focus of x2 = 4ay is(0,a) so compare it with x^2=y this implies 4a=1 or a=1/4 so it is(0,1/4).k
 one year ago

AperogalicsBest ResponseYou've already chosen the best response.0
now you have 2 points p(2,4) and focus f(0,1/4) so can u draw a line???????????
 one year ago

lilsis76Best ResponseYou've already chosen the best response.0
dw:1352585497197:dw
 one year ago

AperogalicsBest ResponseYou've already chosen the best response.0
so thats ur focal chord any chord passing through focus is called focal chord:)
 one year ago

lilsis76Best ResponseYou've already chosen the best response.0
let me write that down
 one year ago

lilsis76Best ResponseYou've already chosen the best response.0
did i make the line right?
 one year ago

AperogalicsBest ResponseYou've already chosen the best response.0
ya you make it right:) sry i didn't noticed ur reply:( @lilsis76
 one year ago

lilsis76Best ResponseYou've already chosen the best response.0
haha its okay. but thank u for letting me know. Okay whats next what do i have to do?
 one year ago

AperogalicsBest ResponseYou've already chosen the best response.0
dw:1352586259141:dw now what is the coordinate of any point on parabola?????
 one year ago

lilsis76Best ResponseYou've already chosen the best response.0
wait, its a normal looking parabola with the point (0,0) right? thats how you got that parabolas shape?
 one year ago

lilsis76Best ResponseYou've already chosen the best response.0
im sorry im kinda new to this lol
 one year ago

lilsis76Best ResponseYou've already chosen the best response.0
since you said any point. ill go to the left. the Q would be P's opposite and be .. 2,4? right?
 one year ago

AperogalicsBest ResponseYou've already chosen the best response.0
well it is not what i asked i asked general form it is(x,x^2) :) as PFQ is a straight line so slope of PF=FQ now find their slopes...........when u solve this completely i will tell you a short method:)
 one year ago

lilsis76Best ResponseYou've already chosen the best response.0
okay. im trying to do PF, is that ...getting the 2*1/4?
 one year ago

lilsis76Best ResponseYou've already chosen the best response.0
hmm... let me try again
 one year ago

lilsis76Best ResponseYou've already chosen the best response.0
WAIT let me try again
 one year ago

lilsis76Best ResponseYou've already chosen the best response.0
i got..... 4  1/4 / 20
 one year ago

lilsis76Best ResponseYou've already chosen the best response.0
dw:1352587321957:dw i dont know how to work out the fraction and whole number
 one year ago

AperogalicsBest ResponseYou've already chosen the best response.0
slope m=dw:1352587256238:dw solve for x i just compare the two slopes:)
 one year ago

AperogalicsBest ResponseYou've already chosen the best response.0
@lilsis76 is it value of x?????????
 one year ago

lilsis76Best ResponseYou've already chosen the best response.0
oh. well then imma say yes it is then
 one year ago

AperogalicsBest ResponseYou've already chosen the best response.0
dw:1352587871193:dw
 one year ago

lilsis76Best ResponseYou've already chosen the best response.0
how did you get the 13/8?
 one year ago

AperogalicsBest ResponseYou've already chosen the best response.0
dw:1352588075547:dw so x=1/8 or 2
 one year ago

AperogalicsBest ResponseYou've already chosen the best response.0
coordinates are (x,x^2) from fig x<0 x cannot be =2 Q=(1/8,1/16)
 one year ago

lilsis76Best ResponseYou've already chosen the best response.0
and the 2, did you just add the 1/8 th twice to get 1/16?
 one year ago

AperogalicsBest ResponseYou've already chosen the best response.0
now shortcut method:) Let y2 = 4ax be the equation of a parabola and (at^2, 2at) a point P on it. Suppose the coordinates of the other extremity Q of the focal chord through P are (at1^2, 2at1). then t1=1/t:) so dw:1352588333605:dw
 one year ago

AperogalicsBest ResponseYou've already chosen the best response.0
no @lilsis76 as the coordinates are(x,x^2)
 one year ago

AperogalicsBest ResponseYou've already chosen the best response.0
@lilsis76 did u got it?????????
 one year ago

lilsis76Best ResponseYou've already chosen the best response.0
kinda, not really. okay well i ended up getting the  1/8 for x, i plug it in right?
 one year ago

lilsis76Best ResponseYou've already chosen the best response.0
ok i got 8x+1 an x2, x= 1/8, x=2
 one year ago

AperogalicsBest ResponseYou've already chosen the best response.0
now go ahead for shortcut:)
 one year ago

lilsis76Best ResponseYou've already chosen the best response.0
the shortcut u gave me?
 one year ago

lilsis76Best ResponseYou've already chosen the best response.0
anywho, i did the math cuz shortcut got me lost. i have x = 1/8 and x=2
 one year ago
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