HP 39G

Using mathematical functions 10-25
To find the
indefinite integral
using formal
variables
For example, to find the indefinite integral of
use:
1. Enter the function.
>6+,)7@>GG[@0>@
>$/3+$@S1 >@ 3 >[@
>$/3+$@X >[@>@ 5 > @
>$/3+$@X>@ >(17(5@
HINT If the Decimal Mark setting in the Modes input form
(>6+,)7@MODES)is set to Comma, use >@ instead of >@.
2. Show the result format.
*k,
6+2:_
3. Press
2._ to close the
show window.
4. Copy the result and evaluate.
&23<_ >(17(5@
Thus, substituting X for S1, it can be seen that:
This result derives from substituting X=S1 and X=0 into the
original expression found in step 1. However, substituting
X=0 will not always evaluate to zero and may result in an
unwanted constant.
To see this, consider:
3x
2
5– xd
∫
0 S13X
2
, 5 X,–,()
∫
HP 39G
HP 40G
3x
2
5– x 5x–3
x
3
3
-----
X∂
∂
X()
---------------





+=d
∫
x 2–()
4
x
x( 2)
5
–
5
-------------------
=d
∫