PAYMENT()
 Computes the periodic payment amount
------------------------------------------------------------------------------
 Syntax

     PAYMENT(<nCapital>,<nInterestRate>,<nNumberpayments>,)
         --> nPayment

 Arguments

     <nCapital>  Designates the loan amount.

     <nInterestRate>  Designates the periodic interest rate.  1
     corresponds to 100%.

     <nNumberPayments>  Designates the number of payments on the loan
     within the payment period.

 Returns

     PAYMENT() returns the payment to make for each payment period.

 Description

     PAYMENT() computes the payment for each period where loan interest
     applies.  The determined amount relates to a loan amount <nCapital> that
     is repaid over <nNumberPayments>, at an interest rate of
     <nInterestRate>.

 Example

     How high does the monthly annuity amount have to be, if you want to
     repay a $2,000.00 loan within 24 months at an annual interest rate of
     10%:

     nRate  :=  0.1/12              // The monthly rate
     ? PAYMENT(2000, Rate, 24)      // 92.29 per month