The two right-most
menu
labels,
DEC
(degrees)
and
RAD
(radians),
represent your choices of angle mode. Note
that
the
DEC
label
shows
a small square, indicating
that
the
current angle
mode
is
Degrees.
Select Radians angle mode.
RAD
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.
I TRIG I
These are
one-number
functions, acting
on
the
number
in level
1.
For
real numbers,
the
angle
mode
affects
how
SIN (sine), COS (cosine),
and
TAN (tangent) interpret their arguments,
and
how
ASIN (arc sine),
ACOS (arc cosine),
and
ATAN
(arc tangent) express their results.
You'll use
the
SIN function in
the
discussion
of
7r
that
comes next.
Using 7r
The transcendental
number
7r
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
IT
that
represents
7r
ex-
actly. In
radians
angle mode,
the
functions SIN, COS,
and
TAN
recognize
the
symbolic constant
IT
and
produce
an
exact result. The
functions SIN
and
COS also recognize
IT
/ 2.
74
5:
Real-Number
Functions
To Next Page
Loading...
Need help?
General
