239
Appendix
2. Error conditions during financial calculations
• r
≤
-
1
• N = 0 in PMT calculations
• I% = 0 and PMT = 0, or I%
≠
0 and FV = (1/r) (1
+
r
×
s)
×
PMT, in N calculations.
s = 1 (Pmt_Begin)
s = 0 (Pmt_End)
In I% calculations
If PMT > 0:
Pmt_End mode:
PV
≥
0 and FV
+
PMT
≥
0
PV < 0 and FV
+
PMT < 0
Pmt_Begin mode: PV
+
PMT
≥
0 and FV
≥
0
PV
+
PMT < 0 and FV < 0
If PMT < 0:
Pmt_End mode:
PV > 0 and FV
+
PMT > 0
PV
≤
0 and FV
+
PMT
≤
0
Pmt_Begin mode: PV
+
PMT > 0 and FV > 0
PV
+
PMT
≤
0 and FV
≤
0
If PMT = 0: PV
÷
FV
≥
0
• FV, N
×
PMT, PV
≥
0 or FV, N
×
PMT, PV
≤
0
• Irr calculation: all cash flows have the same sign.
3. Distribution function
1
pdfnorm(
1
f (x) =
exp (
–
)
(x
–
µ
)
2
2
σ
2
2
πσ
2
pdfT(
f (x) =
π
df
df
2
x
2
df
df
+
1
2
df
+
1
2
-
Γ
( )
Γ
( ) (1
+
)
Calculation result
→
Xreg
Calculation result
→
Xreg
µ
: Mean
s
: Standard
deviation
However:
Γ
(s) =
∫
∞
0
x
s
–
1
e
-
x
dx