interest_payment

Evaluates the interest payment for an investment for a given period.

Synopsis

#include <imsl.h>

float imsl_f_interest_payment (float rate, int period, int n_periods, float present_value, float future_value, int when)

The type double function is imsl_d_interest_payment.

Required Arguments

float rate (Input)
Interest rate.

int period (Input)
Payment period.

int n_periods (Input)
Total number of periods.

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

float future_value (Input)
The value, at some time in the future, of a current amount and a stream of payments.

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 see the Usage Notes section of this chapter.

Return Value

The interest payment for an investment for a given period. If no result can be computed, NaN is returned.

Description

Function imsl_f_interest_payment computes the interest payment for an investment for a given period.

It is computed using the following:

 

 

Example

In this example, imsl_f_interest_payment computes the interest payment for the second year of a 25-year $100,000 loan with an annual interest rate of 8%. The payment is made at the end of each period.

 

#include <stdio.h>

#include <imsl.h>

 

int main()

{

float rate = .08;

int period = 2;

int n_periods = 25;

float present_value = 100000.00;

float future_value = 0.0;

int when = IMSL_AT_END_OF_PERIOD;

float interest_payment;

 

interest_payment = imsl_f_interest_payment (rate, period, n_periods,

present_value, future_value, when);

printf ("The interest due the second year on the $100,000 ");

printf ("loan is $%.2f.\n", interest_payment);

}

Output

 

The interest due the second year on the $100,000 loan is $-7890.57.