HP 33s |X, |X, 8–7, Integrating Equations 8–7, Example: Changing the Accuracy

X	!!		The integral approximated to
	≥ /		two decimal places.
	)	
[	)	.	The uncertainty of the
			approximation of the integral.

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:Display:Description:

{ } 4	) .
	)
	)
H	1%2ª%
X	!!
	≥ /
	) 
[	)  .
{%} 4	)

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