Discriminants
What is a discriminant?
- The discriminant is the part of the quadratic formula that is under the square root sign
- It is
- The quadratic formula, in full, is
where the quadratic equation is written in the form
- It is sometimes denoted by the Greek letter (capital delta)
Worked example
Find, in terms of the constant , the discriminant of the quadratic equation .
First write the quadratic equation in the form .
It can be easier/clearer to pick out and first, before finding the discriminant.
The discriminant is .