HP -28S Manual page 60

Clear the stack and select the cursor menu .
• 1
CLEAR
I
If a menu is displayed, press
GEJ
to select the cursor menu.
Put the name
I
F.:
1
I
on the stack.
~ R1
1
ENTER
I
Ii i
'R!
,I
Note that the closing
I
is added for you. You'll leave Rl on the stack
until it's time to add it to the rest of the calculation.
Put the reciprocal of R2 on the stack.
~
R2
1
ENTER
I
.[}E]
'"'4:-:-------------,
3:
2:
1 :
'Ri'
, INV(R2) ,
Put the reciprocal of R3 on the stack.
~
R3
1
ENTER
I
.[}E]
0.
4 - : " : - - - - - - - - - - - - ,
3: 'Ri'
Add the reciprocals of R2 and R3.
CD
Take the reciprocal of the sum .
• [}E]
2: 'INV(R2)'
1: ' INV(R3) ,
4:
3:
2:
1 :
3:
, Ri'
'INV(R2)+INV(R3),
2: 'Ri'
1: 'INV(lNV(R2)+INV(R3)
)
,
4: Repeating Calculations 59
I