HP 33s User Manual page 129

º "
X
w
The integral is 1.61±0.0161. Since the uncertainty would not affect the
approximation until its third decimal place, you can consider all the displayed
digits in this approximation to be accurate.
If the uncertainty of an approximation is larger than what you choose to tolerate,
you can increase the number of digits in the display format and repeat the
integration (provided that f(x) is still calculated accurately to the number of digits
shown in the display), In general, the uncertainty of an integration calculation
decreases by a factor of ten for each additional digit, specified in the display
format.
Example: Changing the Accuracy.
For the integral of Si(2) just calculated, specify that the result be accurate to four
decimal places instead of only two.
Keys:
Þ
{  } 4
< <
º d
º "
X
w
Þ
{  } 4

∫

 

 

Display:
 

 

 



∫

 

 


The integral approximated to
two decimal places.
The uncertainty of the
approximation of the integral.
Description:
Specifies accuracy to four
decimal places. The uncertainty
from the last example is still in
the display.
Rolls down the limits of
integration from the Z– and
T–registers into the X– and
Y–registers.
Displays the current equation.
Calculates the result.
Note that the uncertainty is
about 1/100 as large as the
uncertainty of the SCI 2 result
calculated previously.
Restores FIX 4 format.
Integrating Equations
8–7