HP -15C Advanced Functions Handbook page 54

52
Section 2: Working With f/F]
Keystrokes Display
| ENTER |
fGSBll
| ENTER |
225| ENTER |
[ENTERj[ENTER|
2
2
2
2
.000
768
250
250
02
-85
02
02
Calculator doesn't
underflow at x = 200; try a
number between 200 and
250.
GSBI1
4.324 -96
Calculator is close to
underflow.
At this point, you can use | SOLVE] to pinpoint the smallest value of x
at which the calculator underflows.
Keystrokes
SB
Display
2.250 02
2.280 02
Roll down stack until the
last value tried is in the X-
and Y-registers.
The minimum value of x
at which the calculator
underflows is about 228.
You've now determined that you need integrate only from 0 to 228.
Since the integrand is interesting only for values of x less than 10,
divide the interval of integration there. The problem has now
become:
/
xe
x
dx
0
Keystrokes
7fnfpiMlf(i)1
m CLEAR rr+i
0| ENTER |
r2m /-]
^ / xe~
x
dx — 1
J
o JQ
Display
7.000 00
0.000 00
0.000 00
10
xe
x
dx
r22
Vio
xe
x
dx.
10 10
Allocates statistical
storage registers.
Clears statistical storage
registers.
Keys in lower limit of
integration over first
subinterval.
Keys in upper limit of
integration over first
subinterval.