Question

How to find the discriminant of a parabola?

Answer 1

Y=-0.2x^2+1.62x+4 is the quadratic equation, I'm trying to find the discriminant but I'm stuck on how.

Answer 2

take what ever is under the root sign from the quadratic formula:
\[Dis =b^2-4ab\]

this will give you clues as to how many roots the parabola has

Answer 3

the equation you have listed:
\[y= -0.2x^2+1.62x+4\]
is not the quadratic equation, but rather the standard form of a quadratic function

Answer 4

match your equation to the standard from
\[ a x^2 +b x+c =0 \]
in your case a= -0.2, b=1.62 and c=4
now use the formula (see Mathmuse post)

See http://www.mathwarehouse.com/quadratic/discriminant-in-quadratic-equation.php