Question

Devise an app (use a GUI) to calculate and display loan repayments. The user will enter in a loan amount, term and interest rate. You calculate the periodic amount due and display it to the user. The formula you need is below. A=P{\frac {i(1+i)^{n}}{(1+i)^{n}-1}}={\frac {P\times i}{1-(1+i)^{{-n}}}}=P\left(i+{\frac {i}{(1+i)^{n}-1}}\right) where: A = periodic payment amount P = amount of principal i = periodic interest rate e.g. 7.5% per year / 12 months = 0.625% per period n = total number of payments e.g. 5 years * 12 months = 60 total periods

Answer 1

''' This code has been written in python 3'''

from tkinter import *

master = Tk()
master.title("Periodic Amount Due")
'''Defining Variable to be used in text variable of entry'''
periodicAmount = DoubleVar()
term = DoubleVar()
interestRate = DoubleVar()
loanAmount = DoubleVar()

''' Define Label for the entry field with grid'''
Label(master, text='Loan Amount').grid(row=0)
Label(master, text='Term').grid(row=1)
Label(master, text='Interest Rate').grid(row=2)
Label(master, text='Periodic Amount due').grid(row=4)

'''Which label will records which data'''
e1 = Entry(master, textvariable=loanAmount)
e2 = Entry(master, textvariable=term)
e3 = Entry(master, textvariable=interestRate)
e4 = Entry(master,textvariable=periodicAmount)
'''UI set'''
e1.grid(row=0, column=1)
e2.grid(row=1, column=1)
e3.grid(row=2, column=1)
e4.grid(row=4, column=1)

def getPeriodicAmount():
loanAmount1=loanAmount.get()
term1=term.get()
interestRate1=(interestRate.get()/12)
periodicAmount1 = loanAmount1*(interestRate1*((1+interestRate1)**term1))/(((1+interestRate1)**term1)-1)
periodicAmount.set(round(periodicAmount1,2))

'''Button to get periodic amount due'''
Button(master, text="get", width=10, command=getPeriodicAmount).grid(row=3)

'''Button to close the app'''
Button(master, text="Close the app", width=10, command=master.destroy).grid(row=5)
mainloop()

OUTPUT: