数学建模习题8.9

`def calculate_monthly_payment(P, annual_interest_rate, n_years):
monthly_interest_rate = annual_interest_rate / 12 / 100
total_months = n_years * 12
M = P * (monthly_interest_rate / (1 - (1 + monthly_interest_rate) ** (-total_months)))
return M

loan_amount = 400000
annual_interest_rate = 0.36 # 年利率应该是0.36，而不是0.36 * 12
loan_term_years = 30
monthly_payment = calculate_monthly_payment(loan_amount, annual_interest_rate, loan_term_years)
print(f"每月还款额为：{monthly_payment:.2f}元")
print("学号：05")`