Operation Manual

190 Appendix E: Formulas Used
Sum-of-the-Years-Digits Depreciation
SOYD
k
=
where W = integer part of k
F = fractional part of k.
(i.e., for k = 12.25 years, W = 12 and F = 0.25).
Keyboard function:
DPN
j
=
Program for partial year:
DPN
1
=
DPN
j
= for j ≠ 1
where LADJ =
Declining-Balance Depreciation
Keyboard function:
DPN
j
= for j = 1, 2, …, L
Program for partial first year:
DPN
1
=
DPN
j
= for j ≠ 1
Modified Internal Rate of Return
n = number of compounding periods.
NFV
P
= Net future value of the positive cash flows.
NPV
N
= Net present value of the negative cash flows.
W 1+()W 2F+()
2
------------------------------------------
Lj– 1+()
SOYD
L
-------------------------
SBV SAL–()⋅
L
SOYD
----------------


Y
1
12
------


SBV SAL–()⋅⋅
LADJ j– 2+
SOYD
LADJ
--------------------------------


SBV D
1
– SAL–()⋅
L
Y
1
12
------


–
RBV
j 1–
FACT
100L
---------------
⋅
SBV
FACT
100L
---------------
Y
1
12
------
⋅⋅
RBV
j 1–
FACT
100L
---------------
⋅