## anonymous one year ago Find the standard form of the equation of the parabola with a focus at (7, 0) and a directrix at x = -7.

1. anonymous

lol this might be 12 grade work lol cuz i never heard of it

2. anonymous

its precalc @*ImaBeMe*

3. anonymous

do you know whats special about a focus and directrix

4. anonymous

kinda not really @dan915

5. anonymous

okay basically for focus if u fire any line at into the parabola it will reflect off into the focus

6. anonymous

ok @nanaruiz123

7. anonymous

|dw:1440020061995:dw|

8. anonymous

|dw:1440020159826:dw|

9. anonymous

like that all vertical lines that bounce off the parabola will reflect into the focus

10. anonymous

|dw:1440020223165:dw|

11. anonymous

do you understand the focus now?

12. anonymous

yes but is there an equation i cant use or something @dan915

13. anonymous

well u are gonna solve for that

14. anonymous

you need to know what a focus and directrix is to solve for it

15. anonymous

|dw:1440020416431:dw|

16. anonymous

the vertex has to be at 0,0 because it has to be in the middle of the directrix and the focus now you need some more points so you can solve for the whole parabola equation

17. anonymous

|dw:1440020622812:dw|

18. anonymous

|dw:1440020708157:dw|

19. anonymous

wait im confused? @dan915

20. campbell_st

here is an easy method that uses the focal length and the standard form in this case of \[4a(x - h) = (y - k)^2\] (h, k) is the focus and a is the focal length|dw:1440022451273:dw|