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 2πb 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 man-made 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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