Question : basic quadratic question

Hi

It's been so long since I've done quadratics that I can't remember them but one has just come up in this calculus question I'm doing.

The equation is (2x^2 - 8x + 5) which has roots 2 +/- sqrt(6)/2. I'm happy with how you get the roots.

The question in the book then factorises this quadratic as 2(x-(2-sqrt(6)/2))(x-(2+sqrt(6)/2)).

I don't understand this step. I can see you could take the 2 out of the quadratic to get
2(x^2 - 4x + 5/2) and that the roots of this equation are still the same

But why can you write this: (x-(2-sqrt(6)/2))(x-(2+sqrt(6)/2)).

It looks like you are writing (x-root1)(x-root2)



Thanks

Answer : basic quadratic question

The first thing I think when I read your question is that you have a pretty good grasp of javascript but seem to think there is some sort of "plugin system" for jQuery.  Truth is, there is a very nice way to develop your own functions and extend jQuery (as you mention $.fn.), but after that it's the wild wild west.

I have two suggestions for you.  The first is to get the UN-minified version of whatever autocomplete plugin you have gotten your hands on and invest the hour or so it should take (provided it's properly commented/designed) to look at what it does.  There will almost certainly be sections that deal with "keyup()" and ".click()" that should be pretty clear as to their purpose.

Many plugins include a way to add your own callback handler during certain events (i.e. a value is selected).  I have been using this one lately - http://www.devbridge.com/projects/autocomplete/jquery/.  It has an onSelect() method that you can assign a function to.  From there, you can manipulate the rest of your DOM depending on the value the user selects.