Money deposited in a bank account earns interest on the initial amount deposited as well as any interest earned as time passes. This compound interest can be described by the expression [math]P(1 + r)^n[/math], where [math]P[/math] represents the initial amount deposited, [math]r[/math] represents the interest rate, and [math]n[/math] represents the number of years that pass. How does a change in each variable affect the value of the expression?