Papers
Skills
Learn
PLUS
News
Guides
About
Skills
/
Quadratic discriminant
Quadratic discriminant
In 59 past-paper questions
What this skill is
Using the quadratic discriminant to determine the number of real roots and establish conditions, together with the relationships
α
+
β
=
−
b
/
a
\alpha+\beta=-b/a
α
+
β
=
−
b
/
a
and
α
β
=
c
/
a
\alpha\beta=c/a
α
β
=
c
/
a
between the roots and coefficients of
a
x
2
+
b
x
+
c
=
0
ax^2+bx+c=0
a
x
2
+
b
x
+
c
=
0
, where
a
≠
0
a\ne0
a
=
0
.
