HP -34C Owner's Handbook Manual page 266

264 A More Detailed Look at (3)
Before subdividing the interval of integration, check whether the calcu-
lator underflows when evaluating the function around the upper (or
lower) limit of integration.* Since there is no point in evaluating the
function at values ofx for which the calculator underflows, in some cases
the upper limit of integration can be reduced, saving considerable
calculation time.
Remember that once you have keyed in the subroutine that evaluates
f(x), you can calculate f(x) for any value of x by keying that value into
the X-register and pressing followed by the
label of the subroutine.
If the calculator underflows at the upper limit of integration, try smaller
numbers until you get closer to the point where the calculator no longer
underflows.
Keystrokes Display
(EEX) 3 1. 03 Key upper limit into
X-register.
1.000 03 Fill the stack with x.
1 0.000 00 Calculator underflows at the
upper limit.
300
3.000 02 Try a smaller value of x.
1 0.000 00 Calculatorstill underflows.
200
2.000 02 Try a smaller value of x.
1 2,768 -85 Calculator does not under-
flow at x = 200; try a num-
ber between 200 and 250.
225
2.250 02
1 4.324 -96 Calculatoris close to
underflow.
At this point, you can use to pinpoint the smallest value of x at
which the calculator underflows.
* Rememberthat when the calculation of any quantity would result in a number less than
10-%, the result is replaced by zero. This condition is known as underflow.