Answer:
M = $128,000 * [(p + 0.02) / 12] * [1 + (p + 0.02) / 12]^360 / [[1 + (p + 0.02) / 12]^360 - 1]
Explanation:
If you must know how to solve it
The monthly payment for a mortgage can be calculated using the formula:
M = P * r * (1 + r)^n / [(1 + r)^n - 1]
where M is the monthly payment, P is the loan amount, r is the monthly interest rate, and n is the number of months.
In this case, the Wilsons want to borrow $128,000. We can use the given function APR(p) = p + 0.02 to find the annual interest rate. If p is the prime interest rate as a decimal, then the annual interest rate is APR(p) = p + 0.02.
To convert the annual interest rate to a monthly interest rate, we use the function:
(APR) / 12
So we have:
APR(p) / 12 = (p + 0.02) / 12
Now we can substitute this expression for r in the mortgage payment formula:
M = P * [(p + 0.02) / 12] * [1 + (p + 0.02) / 12]^360 / [[1 + (p + 0.02) / 12]^360 - 1]
where n = 360 since there are 30 years in the loan term.
Substituting P = $128,000 into this formula gives:
M = $128,000 * [(p + 0.02) / 12] * [1 + (p + 0.02) / 12]^360 / [[1 + (p + 0.02) / 12]^360 - 1]