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Putnam
1952 Putnam
A2
A2
Part of
1952 Putnam
Problems
(1)
Putnam 1952 A2
Source:
5/29/2022
Show that the equation
(
9
−
x
2
)
(
d
y
d
x
)
2
=
(
9
−
y
2
)
(9 - x^2) \left (\frac{\mathrm dy}{\mathrm dx} \right)^2 = (9 - y^2)
(
9
−
x
2
)
(
d
x
d
y
)
2
=
(
9
−
y
2
)
characterizes a family of conics touching the four sides of a fixed square.
Putnam