Reference Guide

3-46 Full Command and Function Reference
COS
Type: Analytic Function
Description: Cosine Analytic Function: Returns the cosine of the argument.
For real arguments, the current angle mode determines the number’s interpretation as an angle,
unless the angular units are specified.
For complex arguments, cos(x + iy) = cosx coshy – i sinx sinhy.
If the argument for COS is a unit object, then the specified angular unit overrides the angle mode
to determine the result. Integration and differentiation, on the other hand, always observe the
angle mode. Therefore, to correctly integrate or differentiate expressions containing COS with a
unit object, the angle mode must be set to Radians (since this is a “neutral” mode).
Access: T
Flags: Numerical Results (–3), Angle Mode (–17, –18)
Input/Output:
Level 1/Argument 1 Level 1/Item 1
z
→
cos z
'symb'
→
'COS(symb)'
x_unit
angular
→
cos (x_unit
angular
)
See also: ACOS, SIN, TAN
COSH
Type: Analytic Function
Description: Hyperbolic Cosine Analytic Function: Returns the hyperbolic cosine of the argument.
For complex arguments, cosh(x + iy) = coshx cosy + i sinhx siny.
Access: …Ñ HYPERBOLIC COSH (Ñ is the right-shift of the 8key).
!´ HYPERBOLIC COSH ( ´is the left-shift of the Pkey).
Flags: Numerical Results (–3)
Input/Output:
Level 1/Argument 1 Level 1/Item 1
z
→
cosh z
'symb'
→
'COSH(symb)'
See also: ACOSH, SINH, TANH
COV
Type: Command
Description: Covariance Command: Returns the sample covariance of the independent and dependent data
columns in the current statistics matrix (reserved variable ΣDAT).
The columns are specified by the first two elements in reserved variable ΣPAR, set by XCOL and
YCOL respectively. If ΣPAR does not exist, COV creates it and sets the elements to their default
values (1 and 2).
The covariance is calculated with the following formula:
1
n 1–
------------
x
in
1
x
n
1
–( ) x
in
2
x
n
2
–( )
i 1=
n
∑
where is the ith coordinate value in column n
1
, is the ith coordinate value in the column
n
2
, is the mean of the data in column n
1
, is the mean of the data in column n
2
, and n is the
number of data points.
Access: …µ COV
x
in
1
x
in
2
x
n
1
x
n
2