WOLFRAM|DEMONSTRATIONS PROJECT

Parabolograph

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Parabola: y = x1-
x
a
cot(α)
a
2.1
α
0.7
Prior to the advent of computers, draftsmen had to use dedicated mechanisms to plot curves. One such instrument was the parabolograph [1], simulated in this Demonstration and on display in the London Science Museum [2].
The red pen is connected to a series of bars and sliders. As the pen moves from left to right, it plots the parabola
y=x1-
x
a
cot(α)
. You can vary the parameter
a
with its slider to move the green bar in the mechanism. You can vary the angle
α
with a slider to rotate the magenta bar.