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Derivaiton Of The Quadratic Formula
Many people don`t know where the quadratic formula comes from, it`s not just magic, it actually comes from a quadratic equation
Date : 19/01/2014
Author Information
Uploaded by : Mubariz
Uploaded on : 19/01/2014
Subject : Maths
First you divide both sides by "A" so you get x^2+(Bx/A)+(C/A)=0
Then take "(C/A)" to the other side so you get x^2+(Bx/A)=-C/A
Add "(B/2A)^2" to both sides, so you get
(x^2)+(Bx/A)+(B/2A)^2=-C/A +(B/2A)^2
We can rewrite this as
[x+(B/2A)]^2=-C/A +(B/2A)^2
Now solve for x, we start with square rooting everything, so you get
x+(B/2A)=[-C/A +(B/2A)^2]^0.5 x+(B/2A)=-[-C/A +(B/2A)^2]^0.5 (something to the power of 0.5 is square rooted)
Then we move "(B/2A)" to the other side which gets us
x=-(B/2A)+[-C/A +(B/2A)^2]^0.5 x=-(B/2A)-[-C/A +(B/2A)^2]^0.5 This is solved but we can simplify it, let`s multiply the right by 2A/2A
x=-B+{2A/2A[-C/A +(B/2A)^2]}^0.5 x=-B-{2A/2A[-C/A +(B/2A)^2]}^0.5
Lastly, we can simplify this to get the quadratic formula we all know and love, which is
x={-B+[(B^2)-4AC]^0.5}/2A x={-B-[(B^2)-4AC]^0.5}/2A
Sorry for the bad layout, you can`t really write it well on this, but I hope you learnt something
This resource was uploaded by: Mubariz