1A line of variable length drawn from a fixed origin to a curve.
- ‘When Archimedes defines a spiral, he gives fundamental properties connecting the length of the radius vector with the angles through which it has revolved.’
- ‘In fact, from the point P which is at distance d from the origin measured along a radius vector, the distance from P to the pole is d sec b.’
- ‘The cylindrical coordinate system, (R, Z), was introduced for this boundary, where Z is the axis perpendicular to the plane passing through the boundary, and R is the two-dimensional radius vector in this plane.’
- ‘Three days later he wrote to Le Verrier asking the same question about the radius vector as he had asked Adams.’
- 1.1Astronomy A line joining a satellite or other celestial object to its primary.
- ‘In the second law, Kepler used the idea of radius vector, and stated that the radius vector from the sun to a planet sweeps out equal areas in equal intervals of time.’
- ‘The radius vector is shortest when the planet is at perihelion and longest at aphelion.’
- ‘The radius vector from the sun to a planet sweeps over equal areas in equal times.’
We take a look at several popular, though confusing, punctuation marks.