Question

what is ment by the "discriminant"

Answer 1

The discriminant is b^2-4ac, or the part behind the square root in the quadratic formula. Try this website for more info.
h t t p : / / w w w . r e g e n t s p r e p . o r g / R e g e n t s / m a t h / a l g t r i g / A T E 3/ d i s c r i m i n a n t . h t m
Without the spaces, of course.

Answer 2

When:

y=a*x^2+b*x+c

Then Discriminant is:

Ä=b^2-4*a*c

Go to en.wikipedia organd type "Dioscriminant"