Equation Writer 15-9
Select the fifth branch by 
pressing  . At this point, 
the desired expression is in 
the Equation Writer, as 
shown at the right. 
Suppose that you want to select the second and third 
branches, that is:  . First press    . This selects  , 
the second term.
Now press    . This 
key combination enables 
you to select two contiguous 
branches, the one already 
selected and the one to the 
right of it.
If you want, you can 
evaluate the selected part by 
pressing  . The result 
is shown at the right.
Suppose now you want to 
perform the partial calculation:
Because the two terms in this partial calculation are not 
contiguous (that is, side by side), you must first perform a 
permutation so that they are side by side.To do this, 
press: 
 
This exchanges the selected 
element with its neighbour to 
the left. The result is shown at 
the right.
Now press:
 
to select just the branches 
you are interested in: 
1
3
---
1
4
---
+
1
3
---
1
2
---
1
5
---
+
hp40g+.book  Page 9  Friday, December 9, 2005  12:27 AM