| slovo | definícia |
Parabolic spiral
(gcide) | Parabolic \Par`a*bol"ic\, Parabolical \Par`a*bol"ic*al\, a. [Gr.
paraboliko`s figurative: cf. F. parabolique. See Parable.]
[1913 Webster]
1. Of the nature of a parable; expressed by a parable or
figure; allegorical; as, parabolical instruction.
[1913 Webster]
2. [From Parabola.] (Geom.)
(a) Having the form or nature of a parabola; pertaining
to, or resembling, a parabola; as, a parabolic curve.
(b) Having a form like that generated by the revolution of
a parabola, or by a line that moves on a parabola as a
directing curve; as, a parabolic conoid; a parabolic
reflector; a parabolic antenna.
[1913 Webster +PJC]
Parabolic conoid, a paraboloid; a conoid whose directing
curve is a parabola. See Conoid.
Parabolic mirror (Opt.), a mirror having a paraboloidal
surface which gives for parallel rays (as those from very
distant objects) images free from aberration. It is used
in reflecting telescopes.
Parabolic spindle, the solid generated by revolving the
portion of a parabola cut off by a line drawn at right
angles to the axis of the curve, about that line as an
axis.
Parabolic spiral, a spiral curve conceived to be formed by
the periphery of a semiparabola when its axis is wrapped
about a circle; also, any other spiral curve having an
analogy to the parabola.
[1913 Webster] |
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