COS Function
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Action
Returns the cosine of an angle given in radians.
Syntax
COS( x)
Remarks
The argument x can be of any numeric type.
The cosine of an angle in a right triangle is the ratio between the length
of the side adjacent to the angle and the length of the hypotenuse.
COS is calculated in single precision if x is an integer or
single-precision value. If you use any other numeric data type, COS is
calculated in double precision.
To convert values from degrees to radians, multiply the angle (in degrees)
times --180
(or .0174532925199433). To convert a radian value to degrees, multiply it by
180-- (or 57.2957795130824). In both cases, - - 3.141593.
See Also
ATN, SIN, TAN
Example
The following example plots the graph of the polar equation r = nq for
values of n from 0.1-1.1. This program uses the conversion factors x =
cos(q) and y = sin(q) to change polar coordinates to Cartesian coordinates.
The figure plotted is sometimes known as the Spiral of Archimedes.
CONST PI = 3.141593
SCREEN 1 . COLOR 7' Gray background.
WINDOW (-4,-6)-(8,2) ' Define window large enough for biggest spiral.
LINE (0,0)-(2.2 * PI,0),1' Draw line from origin to the right.
' Draw 10 spirals.
FOR N = 1.1 TO .1 STEP -.1
PSET (0,0)' Plot starting point.
FOR Angle = 0 TO 2 * PI STEP .04
R = N * Angle' Polar equation for spiral.
' Convert polar coordinates to Cartesian coordinates.
X = R * COS(Angle)
Y = R * SIN(Angle)
LINE -(X,Y),1' Draw line from previous point to new point.
NEXT Angle
NEXT N