Quadratic Functions

You need to know: 

The general formula of a quadratic is \[y=ax^2+bx+c\] where \{a, b, c,\} are constants and \[a \neq 0\]

Quadratic equations can be solved by:

(i) factorisation by D.O.T.S 'ac' method seeing it       

(ii) completing the square      \(x^2\pm bx=(x\pm\frac{b}{2}\))\(^2\)-(\(\frac{b}{2}\))\(^2\)

(iii) using the quadratic formula\(x=\frac{-b\pm\sqrt{b^2-4ac}}{2a}\)

remember plotting \(\neq\) sketching!

How to sketch and get method marks:

\(a > 0\) then \(\cup\) , \(a \(b^2-4ac > 0\) there are 2 real different roots, \(b^2-4ac=0\) there are 2 equal \(R\) roots, \(b^2-4ac \(x\)-axis crossing \(y\)-axis crossing

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