## Archimedean spiralOn Spirals. The Archimedean spiral has a very simple
equation in polar coordinates
(r, θ): r = a + bθ
where a and b can be any real numbers. Changing the parameter
a turns the spiral, while b controls the distance between
the arms. The Archimedean spiral is distinguished from the logarithmic spiral by the fact that successive arms have a fixed distance (equal to 2π b if θ is measured in radians),
whereas in a logarithmic spiral these distances form a geometric
sequence. Note that the Archimedean spiral has two possible arms that coil in opposite directions, one for θ > 0 and the other for θ
< 0. Many examples of spirals in the manmade world, such as a watch spring
or the end of a rolled carpet, are either Archimedean spirals or another
curve that is very much like it – the circle
involute. ## Related category• PLANE CURVES | ||||||

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