202 Section 14: Numerical Integration
If the uncertainty of an approximation is larger than what you choose to
tolerate, you can decrease it by specifying a greater number of digits in the
display format and repeating the approximation.
*
Whenever you want to repeat an approximation, you don't need to key the
limits of integration back into the X- and Y-registers. After an integral is
calculated, not only are the approximation and its uncertainty placed in the
X- and Y-registers, but in addition the upper limit of integration is placed in
the Z-register, and the lower limit is placed in the T-register. To return the
limits to the X- and Y-registers for calculating an integral again, simply
press ) ).
Example: For the integral in the expression for J
1
(l), you want an answer
accurate to four decimal places instead of only two.
The uncertainty indicates that this approximation is accurate to at least four
decimal places. Note that the uncertainty of the i 4 approximation is
about one-hundredth as large as the uncertainty of the i 2
approximation. In general, the uncertainty of any f approximation
decreases by about a factor of 10 for each additional digit specified in the
display format.
*
Provided that f(x) is still calculated accurately to the number of digits shown in the display.