Final answer:
The monthly payments on a mortgage, represented by the function P = f(A, r, t), are an increasing function of the borrowed amount A.
Step-by-step explanation:
The function P = f(A, r, t) represents the monthly payments on a mortgage. To determine whether the function is increasing or decreasing with respect to A, we need to consider the partial derivative of P with respect to A.
The partial derivative ∂P/∂A represents the rate of change of P with respect to A. If ∂P/∂A is positive, the function is increasing with respect to A. If ∂P/∂A is negative, the function is decreasing with respect to A.
To find the partial derivative, we differentiate the function P = f(A, r, t) with respect to A:
∂P/∂A = r * (1+r)^t / ((1+r)^t - 1)
By examining the partial derivative, we can see that it is always positive, which means the function P = f(A, r, t) is an increasing function of A. This implies that as the borrowed amount A increases, the monthly payments P will also increase.