Amount function
A(t), A(0) = Principal
Accumulation Function
a(t) = A(t)/A(0), a(0) = 1
Interest (accounting)
A(t) - A(0)
Compounded Interest
a(t) = (1 + i)^t = e^&t
Simple Interest
a(t) = 1 + it, t = days/365
Nu
v = 1/1+i
Nu with discount rate
v = 1 - d, iv = d, v + d = 1, v + iv = 1
Force of interest function
d/dt (ln (A(t))) or a(t)
Force of Interest relationships
1+i = 1/v = e^& , 1/a(t) = v^t = e^-&t
v + d = 1
d is interest
a(3)/a(1)
Bringing time 0 to time 3, and then time 1 to time 0. Overall bringing time 1 to time 3.
Nominal annual interest rate
i^(m)
Effective periodic interest rate
j = i^(m)/m
J with accumulation function
(1 + j) = a(1/m)
Effective annual interest rate
(i^(m)/m + 1)^m - 1 or (j + 1)^m - 1
Force of interest
1 + i = e^& , nominal interest compounded continually
&
i^(inf)
Real Rate of return (baskets)
i - r / 1 + r
Level certain immediate annuity
an|i = 1 - v^n / i = v + … v^n = v - v^n+ 1 / 1 - v
Cash flow annuity interpretation
1 = ia[n] + v ^n , payments of i with on payment of 1 pulled back n periods.
Geometric sum formula
(First - PastLast)/(1- mult)
Nominal annual discount rate
d^(m)
Effective Periodic discount rate
d^(m)/m
Nominal v and d relationship
v = 1 - d^(m)/m