Computer Forums vertex of a parabola

 10-14-2008, 06:36 PM #1 Fully Optimized     Join Date: Nov 2007 Posts: 3,952 vertex of a parabola can someone tell me how to do this with a trinomial, the trinomial is x(2)+8x-10 please dont rag on the easy math i just cant remember the formula __________________ __________________ My beast lappy: Acer netbook, 1.6ghz atom dual core, 2gb ddr3 My PSN: Kalikid_420
 10-14-2008, 07:04 PM #2 Fully Optimized     Join Date: Jul 2006 Location: USA Posts: 2,410 Re: vertex of a parabola It's -b/2a for the x coordinate. Then plug that x coordinate into the equation for x and find the y coordinate. __________________ __________________ Desktop: Dell Dimension E510, 2.5GB RAM, Intel P4 3.0GHZ, 250GB HDD, Windows Vista Premium. Might not be the best, but the old girl is still running good.
 10-14-2008, 07:15 PM #3 Guru     Join Date: Jan 2008 Location: U.S. Posts: 7,841 Re: vertex of a parabola It's a lot easier with derivatives. In your case let's see: The derivative is 2x + 8. Set that equal to 0. x = -4. The vertex will be at (-4, -26) What troy said is also correct and probably used more often in lower math classes. The only problem is that only holds true to the format ax^2 + bx + c. If you want a quick lesson on how to find derivatives of polynomials give me a PM. It's really simple that you'll be like "Holy ****! My dog can do that!". Once you have the derivative you set it equal to 0 and it will give you x coordinates to all relative vertexes. Or...using a graphing calculator: Graph the polynomial then hit 2nd, trace (will go to calc) and scroll down to maximum/minimum. It will ask for left and right bound then a guess. On left bound, you select a point left of the peak. Right bound, same thing only to the right. Then you guess any point in between, doesn't matter. It will then give you approximations to the actual point if not the exact. __________________
 10-14-2008, 07:30 PM #4 Daemon Poster     Join Date: Nov 2006 Posts: 941 Re: vertex of a parabola I hate to be that dude, but. . . __________________ My word is bond and bond is life and I will give my life before my word shall fail.
10-14-2008, 07:33 PM   #5
Fully Optimized

Join Date: Jun 2006
Posts: 2,841
Re: vertex of a parabola

Quote:
 Originally Posted by Illmatic I hate to be that dude, but. . .
Nice find, but. . .

I tend to ask help for math questions like this rather than google it because I tend to find a real person's explanation to be easier to understand than a PhD. Just my experiences though.
__________________
A+, Network+
Official "Birthday Man" of CF.

http://www.yourpcforums.org