n. 求面积, 正交, 弦

[计] 正交

[ noun ]
the construction of a square having the same area as some other figure
<noun.act>

Quadrature \Quad"ra*ture\, n. [L. quadratura: cf. F. quadrature.
See {Quadrate}, a.]
1. (Math.) The act of squaring; the finding of a square
having the same area as some given curvilinear figure; as,
the quadrature of a circle; the operation of finding an
expression for the area of a figure bounded wholly or in
part by a curved line, as by a curve, two ordinates, and
the axis of abscissas.

2. A quadrate; a square. --Milton.

3. (Integral Calculus) The integral used in obtaining the
area bounded by a curve; hence, the definite integral of
the product of any function of one variable into the
differential of that variable.

4. (Astron.) The position of one heavenly body in respect to
another when distant from it 90[deg], or a quarter of a
circle, as the moon when at an equal distance from the
points of conjunction and opposition.

{Quadrature of the moon} (Astron.), the position of the moon
when one half of the disk is illuminated.

{Quadrature of an orbit} (Astron.), a point in an orbit which
is at either extremity of the latus rectum drawn through
the empty focus of the orbit.