Texas Instruments TI Programmable 57 User Manual

COMBINATIONS:
(ser)
AND
(inv)
(sea)
Let's
consider
a
program
example
from
statistics
thatinvolves
the-usé
of
subroutines.
A
“combination”
calculation
arises
when
thingsare
being
put
together
in
groups
(say
10
items
grouped
3
at
a
time
without
repeating).
The
general
formula
for
the
number
of
ways
n
things
may
be
combined,
r
at
a
time,
is
written
(")
or
,C,
andequals:
__ni
_
(n—r)Ir!
(remember
that
n!
means
“n
factorial”
—
see
Chapter
4).
DESTINATION
You
want
a
program
that
allows
you
to
enter
the
total
number
of
the
things
you
are
looking
at
(n)
and
press
[R4)
;
then
enter
the
number
you
want
in
each
group
r,
press
;
and
the
calculator
will
display
the
number
of
combinations
of
n
things
taken
r
at
a
time
(,@,).
PLANNING THE Route
To
compute
the
factorial,
we'll
use
a
subroutine
that
works
with
the
[2nd]
@™
key
sequence
as
we
described
previously.
We
can
“lift”
the
factorial
program
described
in
that
example
and
use
it
as
a
subroutine
here,
by
just
starting
it
with
a
label,
(label
2),
and
ending
it
with
an
[iNv)
key
sequence.
We'll
calculate
ni,
store
it
in
memory
1;
calculate
rl,
store
it
in
memory
2;
calculate
(n—r)!,
store
it
in
memory
3;
then
use
these
results
to
compute
|
EG
en
(n—r)! r!
Maxine TrACKs
Enter
the
program
carefully
from
the
flow
chart
on
the
next
page.
Runninc It
Using
your
program,calculate
the
number
of
poker
hands
(5
cards)
that
can
be
dealt
from
deck
of
52
cards
(.,C.),
Press
DispLay/CoMMENTS
52
RA)
8.0658175
67
(This
is
52!)
Note: Allow time for your
calculator to finish.
5
RA)
2598960.
the
number
of
possible
poker hands from a 52
card deck (.,C.).
Now
let's
say
you
would
like
to
use
just
the
subroutine
part
of
the
program to find 10!
10
(58a)
2
3628800.
(this
is
10!)
SEE
4-9

Texas Instruments TI Programmable 57 Specifications

General

Brand	Texas Instruments
Model	TI Programmable 57
Category	Calculator
Language	English