How to Derive the annual compound interest formula

In this video tutorial the instructor shows how to derive the formula to compute interest compounded annually. He starts with explaining the basic concepts like principle which is the amount you borrow and the rate of interest or annual percentage rate (APR), which is the rate at which you pay the interest up on the borrowed principle. He shows that the amount after the end of one year is amount A = P(1+APR),and he goes on and generalizes how to compute it for n years. This video shows how to derive a formula to calculate amount where the principle is borrowed at an APR which is compounded annually.