5. (3 points) In the lecture to chapter 4, you learned that an increase in the currency-deposit ratio (Aer > 0) decreases the money multiplier, m. Use calculus to show if this is always true. If not, what are the conditions for this to be true? (Hint: As a first step, you need to take the partial derivative of m with respect to cr. The quatient rule might come in handy.)