Keystrokes display – HP 15c User Manual
Page 45
Section 2: Working with
f
45
Keystrokes
Display
200
v
2.000 00
Try a smaller value of x.
vv
2.000 02
G1
2.768 -85
Calculator doesn’t underflow at
x = 200; try a number between
200 and 250.
225
v
2.250 02
vv
2.250 02
G1
4.324 -96
Calculator is close to underflow.
At this point, you can use _ to pinpoint the smallest value of x at which the calculator
underflows.
Keystrokes
Display
)
2.250 02
Roll down stack until the last
value tried is in the X- and Y-
registers.
´_1
2.280 02
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:
228
0
10
0
228
10
0
dx
xe
dx
xe
dx
xe
dx
xe
x
x
x
x
.
Keystrokes
Display
7
´m%
7.000 00
Allocates statistical storage
registers.
´CLEARz
0.000 00
Clears statistical storage
registers.
0
v
0.000 00
Keys in lower limit of
integration over first subinterval.
10
10
Keys in upper limit of
integration over first subinterval.
´f1
9.995 -01
Integral over (0,10) calculated in
i3.
z
1.000 00
Sum approximation and its
uncertainty in registers R
3
and
R
5
.