cumulative_principal

Evaluates the cumulative principal paid between two periods.

Synopsis

#include <imsl.h>

float imsl_f_cumulative_principal (float rate, int n_periods, float present_value, int start, int end, int when)

The type double function is imsl_d_cumulative_principal.

Required Arguments

float rate (Input)
Interest rate.

int n_periods (Input)
Total number of payment periods. n_periods cannot be less than or equal
to 0.

float present_value (Input)
The current value of a stream of future payments, after discounting the payments using some interest rate.

int start (Input)
Starting period in the calculation. start cannot be less than 1; or greater than end.

int end (Input)
Ending period in the calculation.

int when (Input)
Time in each period when the payment is made, either IMSL_AT_END_OF_PERIOD or IMSL_AT_BEGINNING_OF_PERIOD. For a more detailed discussion on when see the Usage Notes section of this chapter.

Return Value

The cumulative principal paid between the first period and the last period. If no result can be computed, NaN is returned.

Description

Function imsl_f_cumulative_principal evaluates the cumulative principal paid between the first period and the last period.

It is computed using the following:

 

where principali is computed from imsl_f_principal_payment for the i-th period.

Example

In this example, imsl_f_cumulative_principal computes the total principal paid for the first year of a 30-year $200,000 loan with an annual interest rate of 7.25%. The payment is made at the end of each month.

 

#include <stdio.h>

#include <imsl.h>

 

int main ()

{

float rate = 0.0725 / 12;

int n_periods = 12 * 30;

float present_value = 200000;

int start = 1;

int end = 12;

float total;

 

total = imsl_f_cumulative_principal (rate, n_periods, present_value,

start, end, IMSL_AT_END_OF_PERIOD);

 

printf ("First year principal = $%.2f.\n", total);

}

Output

 

First year principal = $-1935.73.