HP 40gs User Manual
Page 285
Step-by-Step Examples
16-11
Now consider the product of two of the definitions
entered above: B(N) × C(N):
B
N
C
N
.
Press ,
to select
EXP2POW and
press .
Press
to evaluate
the expression, yielding the
result of B(N) × C(N).
Consider now the decomposition of A(6) into its prime
factors.
Press ,
to select
FACTOR and press
.
Now press
A
6.
Finally, press
to get
the result. The factors are
listed, separated by a
medial period. In this case,
the factors are 3, 23, 29
and 1999.
Now let’s consider whether b
n
and c
n
are relatively prime.
Here, the calculator is useful only for trying out different
values of n.
To show that b
n
and c
n
are relatively prime, it is enough
to note that:
That means that the common divisors of b
n
and c
n
are the
common divisors of b
n
and 2, as well as the common
divisors of c
n
and 2. b
n
and 2 are relatively prime
because b
n
is a prime number other than 2. So:
c
n
b
n
2
+
=
hp40g+.book Page 11 Friday, December 9, 2005 1:03 AM