#I need help alg 2
49 messages · Page 1 of 1 (latest)
help ples
Well you're right that it is a parabola
Are you familiar with completing the square?
nope
Were you given any formulas for computing the coordinates of the vertex of a parabola?
Hmm not exactly. This shows parabolas that have vertex at the origin (0,0).
The one in your problem is translated with a vertex at (h,k).
oh yeah yeah
Something like $h = \frac{-b}{2a}$
Azyrashacorki
nope
well i recorded the lesson earlier
she solved it like this
wait wrong pic
well no
i mean the way she teaches us kinda weird
because when it comes to like homework and shit like everything is diff
Do you have formulas to compute the directrix and the focus then? Because here again the vertex is at (0,0).
It's not you being dumb I'm just trying to think of ways to compute the coordinates of the vertex the way your classes might've shown
Once that's dealt with finding p is relatively easy.
do you wanna see the answer? because i can re do it
In any case this works
No it's ok I know how to do it, it's just there are multiple ways to go about it I don't want to show you stuff that will confuse you if you've not seen them in class.
So if you have $y= ax^2 + bx + c$, the vertex is at $(h,k)$ where $h = \frac{-b}{2a}$ and $k = ah^2 = bh + c$.
Azyrashacorki
And $p = \frac{1}{4a}$
Azyrashacorki
Those formulas are how it's done tbh
Otherwise as I pointed out earlier there's square completion :
$3x^2 + 30x + 68 = 3(x^2 + 10x + \frac{68}{3})$.
Now $$x^2 + 10x = (x+5)^2 - 25$$, so you get $$y = 3((x+5)^2 -25 + \frac{68}{3}) = 3((x+5)^2 - \frac{7}{3} = 3(x+5)^2 - 7.$$
Send the 7 to the other side and you get $y+7 = 3(x+5)^2$ and you have pretty much all the information for h, k and p.
Azyrashacorki
BRUH
AINT NO WAY THATS IT
THANK YOU
GOOD LUCK ON YO LEAGUE
.done
how do yo end this shit
.done
/done
.close