The two right-most menu labels,
represent your choices of angle mode. Note that the
shows a small square, indicating that the current angle mode is
Select Radians angle mode.
The Radians annunciator (21r) appears and the menu labels change.
(Most illustrations in this manual don't show the annunciators. To lo-
cate the (21r) annunciator, see the illustration on page 27.)
Display the first row of the TRIG menu.
These are one-number functions, acting on the number in level 1. For
real numbers, the angle mode affects how SIN
interpret their arguments, and how ASIN
express their results.
You'll use the SIN function in the discussion of
that comes next.
The transcendental number
can't be represented exactly in a finite
decimal form. In general, the calculator's 12-digit approximation
(3.14159265359) yields results accurate to 12 digits, which is suffi-
cient for most applications.
The HP-28S also offers a symbolic constant
actly. In radians angle mode, the functions SIN, COS, and TAN
recognize the symbolic constant
and produce an exact result. The
functions SIN and COS also recognize
5: Real-Number Functions