KAlgebra/Credit payment

Formula for calculating compound interest:

Where,

A = final amount

P = principal amount (initial investment)

r = annual nominal interest rate (as a decimal)

n = number of times the interest is compounded per year(12 times)

t = number of years

Write all these functions in Console Mode

1.This Function calculates the monthly interest rate by given yearly interest rate.

monthlyInterestRate:= yearlyInterestRate-> yearlyInterestRate/1200

2.This function calculates the monthly payment

monthlyPayment:=(sum, mir, months)->(sum*(1+mir)^months*mir)/((1+mir)^months-1)

3.This Function calculates the whole amount you have to return to the bank

amount:=(monthlyPayment,months)->monthlyPayment*months