A community for students.
Here's the question you clicked on:
 0 viewing
lilsis76
 2 years 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.
lilsis76
 2 years 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.

This Question is Closed

lilsis76
 2 years ago
Best ResponseYou've already chosen the best response.0whats a focal chord? I was givin this homework problem and instructor confused me on all the different positions

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

Aperogalics
 2 years ago
Best ResponseYou've already chosen the best response.0@lilsis76 tell me the focus of ur parabola?????:)

lilsis76
 2 years ago
Best ResponseYou've already chosen the best response.0well, it didnt give me a focus it just gave me the P at (2,4)

lilsis76
 2 years ago
Best ResponseYou've already chosen the best response.0it also says the parabola is y=x^2 so...um the p, 1/4

Aperogalics
 2 years ago
Best 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

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

Aperogalics
 2 years ago
Best ResponseYou've already chosen the best response.0so thats ur focal chord any chord passing through focus is called focal chord:)

lilsis76
 2 years ago
Best ResponseYou've already chosen the best response.0let me write that down

lilsis76
 2 years ago
Best ResponseYou've already chosen the best response.0did i make the line right?

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

lilsis76
 2 years ago
Best ResponseYou've already chosen the best response.0haha its okay. but thank u for letting me know. Okay whats next what do i have to do?

Aperogalics
 2 years ago
Best ResponseYou've already chosen the best response.0dw:1352586259141:dw now what is the coordinate of any point on parabola?????

lilsis76
 2 years ago
Best ResponseYou've already chosen the best response.0wait, its a normal looking parabola with the point (0,0) right? thats how you got that parabolas shape?

lilsis76
 2 years ago
Best ResponseYou've already chosen the best response.0im sorry im kinda new to this lol

lilsis76
 2 years ago
Best ResponseYou've already chosen the best response.0since you said any point. ill go to the left. the Q would be P's opposite and be .. 2,4? right?

Aperogalics
 2 years ago
Best ResponseYou've already chosen the best response.0well 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:)

lilsis76
 2 years ago
Best ResponseYou've already chosen the best response.0okay. im trying to do PF, is that ...getting the 2*1/4?

lilsis76
 2 years ago
Best ResponseYou've already chosen the best response.0hmm... let me try again

lilsis76
 2 years ago
Best ResponseYou've already chosen the best response.0i got..... 4  1/4 / 20

lilsis76
 2 years ago
Best ResponseYou've already chosen the best response.0dw:1352587321957:dw i dont know how to work out the fraction and whole number

Aperogalics
 2 years ago
Best ResponseYou've already chosen the best response.0slope m=dw:1352587256238:dw solve for x i just compare the two slopes:)

Aperogalics
 2 years ago
Best ResponseYou've already chosen the best response.0@lilsis76 is it value of x?????????

lilsis76
 2 years ago
Best ResponseYou've already chosen the best response.0oh. well then imma say yes it is then

Aperogalics
 2 years ago
Best ResponseYou've already chosen the best response.0dw:1352587871193:dw

lilsis76
 2 years ago
Best ResponseYou've already chosen the best response.0how did you get the 13/8?

Aperogalics
 2 years ago
Best ResponseYou've already chosen the best response.0dw:1352588075547:dw so x=1/8 or 2

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

lilsis76
 2 years ago
Best ResponseYou've already chosen the best response.0and the 2, did you just add the 1/8 th twice to get 1/16?

Aperogalics
 2 years ago
Best ResponseYou've already chosen the best response.0now 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

Aperogalics
 2 years ago
Best ResponseYou've already chosen the best response.0no @lilsis76 as the coordinates are(x,x^2)

Aperogalics
 2 years ago
Best ResponseYou've already chosen the best response.0@lilsis76 did u got it?????????

lilsis76
 2 years ago
Best ResponseYou've already chosen the best response.0kinda, not really. okay well i ended up getting the  1/8 for x, i plug it in right?

lilsis76
 2 years ago
Best ResponseYou've already chosen the best response.0ok i got 8x+1 an x2, x= 1/8, x=2

Aperogalics
 2 years ago
Best ResponseYou've already chosen the best response.0now go ahead for shortcut:)

lilsis76
 2 years ago
Best ResponseYou've already chosen the best response.0the shortcut u gave me?

lilsis76
 2 years ago
Best ResponseYou've already chosen the best response.0anywho, i did the math cuz shortcut got me lost. i have x = 1/8 and x=2
Ask your own question
Sign UpFind more explanations on OpenStudy
Your question is ready. Sign up for free to start getting answers.
spraguer
(Moderator)
5
→ View Detailed Profile
is replying to Can someone tell me what button the professor is hitting...
23
 Teamwork 19 Teammate
 Problem Solving 19 Hero
 Engagement 19 Mad Hatter
 You have blocked this person.
 ✔ You're a fan Checking fan status...
Thanks for being so helpful in mathematics. If you are getting quality help, make sure you spread the word about OpenStudy.