The monthly payment for a home loan is given by a function f(p,r,n)f(p,r,n) where pp is the principal (the initial size of the loan), rr the interest rate, and nn the length of the loan in months. interest rates are expressed as a decimal: a % interest rate is denoted by r=0.09r=0.09. if p=100000,r=0.09p=100000,r=0.09, and n=216n=216(a 18-year loan), then the monthly payment is f(100000,0.09,216)=816f(100000,0.09,216)=816. furthermore, with these values we have