MathDB
Problems
Contests
Undergraduate contests
Simon Marais Mathematical Competition
2021 Simon Marais Mathematical Competition
A1
A1
Part of
2021 Simon Marais Mathematical Competition
Problems
(1)
Parabola and lines
Source: 2021 Simon Marais, A1
11/2/2021
Let
a
,
b
,
c
a, b, c
a
,
b
,
c
be real numbers such that
a
≠
0
a \neq 0
a
=
0
. Consider the parabola with equation
y
=
a
x
2
+
b
x
+
c
,
y = ax^2 + bx + c,
y
=
a
x
2
+
b
x
+
c
,
and the lines defined by the six equations \begin{align*} &y = ax + b, & y = bx + c, \qquad & y = cx + a, \\ &y = bx + a, & y = cx + b, \qquad & y = ax + c. \end{align*} Suppose that the parabola intersects each of these lines in at most one point. Determine the maximum and minimum possible values of
c
a
\frac{c}{a}
a
c
.
conics
parabola
calculus