Quadrat Function y= a*x^2 + b*x + c,
where a=/=0, a,b,c, X1a and X2 Riel and Discriminan D= b^2 - 4*a*c

Recomended Tasks:
1. Investigate value X1 and X2 of a function by seeing intersection graphic with horizontal line (x)
2. Investigate the form of a graphic if a< 0 for D<0,D=0 and D>0 and do it also if a>0.
3. Explain why graphic (a<0,D<0) is called definit negatif and (a>0,D<0) definit positif?
Clik your mouse on + or - to change the value of a, b and c