When a> 0, the parable has an upward concavity and a minimum point V; when <0, the parable has downward concavity and a maximum point V.
In any case, the coordinates of V are . See the graphics:
Image
The image set Im of the function y = ax^{2} + bx + c, a 0 is the set of values y can assume. There are two possibilities:
1st - when a> 0,
a> 0 |
2nd when a <0,
a <0 |
Next: Parable Construction