polar axis

American  

noun

Mathematics.

1. the fixed line, usually horizontal, from which the angle made by the radius vector is measured in a polar coordinate system.

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polar axis British  

noun

1. the fixed line in a system of polar coordinates from which the polar angle, θ, is measured anticlockwise

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Etymology

Origin of polar axis

First recorded in 1890–95

Example Sentences

By symmetry, the total area is twice the area above the polar axis.

From Textbooks • Mar. 30, 2016

If the directrix of a conic section is perpendicular to the polar axis, what do we know about the equation of the graph?

From Textbooks • Feb. 13, 2015

Since this graph is symmetric with respect to the pole, the line and the polar axis, we only need to plot points in the first quadrant.

From Textbooks • Feb. 13, 2015

The polar grid is scaled as the unit circle with the positive x-axis now viewed as the polar axis and the origin as the pole.

From Textbooks • Feb. 13, 2015

The diurnal motion is compensated by motion about the polar axis only, the other being clamped.

From Pioneers of Science by Lodge, Oliver, Sir