HP -28S Manual page 82

This program means: take an argument from the stack (in RPN syn-
tax) or from the expression (in algebraic syntax) and call it x; then
evaluate the expression
Iltan x,
using the local definition of
x.
Store the program in a variable COT.
CJ
COT
1
STO
I
' - :;:3:-:-:
---~2~.-=0~6
7=-6-:--'1=-=5=3=7=35=7=E=---:"1"=3
2: 0
1: 2.46855006079
CIBIliIUIIlCEIDaIlIillUlGII:m
Now you can use COT in either RPN or algebraic syntax, just like the
built-in trigonometric functions.
Calculate cot 45° using RPN.
.1
MODE
1
DEG
45
1
USER
1
COT
3: 0
2: 2.46855006079
1: 1
. . m. ...
IEJlI _ _
Calculate cot -45° using algebraic syntax.
CJ
co
T
rn -
45
I
ENTER
I
=3-: ------=2,-."""'4-='6"="8=55=0=-0=-6""'0=-=7::-::"1 9
2: 1
Evaluate the expression.
I
EVALI
1:
'COT(-45),
. . m. ...
IEJlI _ _
3: 2.46855006079
2: 1
1: -1
. . m. ...
IEJlI _ _
5: Real-Number Functions 81