Your monthly car payment in dollars is [math]

**(a)**
Is [math]

Suppose that your bank tells you that the magnitude of
[math]

What are the units of this value?

*(For this problem, write our your units in full, writing
dollars for $, months for months,
percent for %, etc. Note that fractional units
generally have a plural numerator and singular denominator.)*

**(b)**
Is [math]

Suppose that your bank tells you that the magnitude of
[math]

What are the units of this value?

*(For this problem, write our your units in full, writing
dollars for $, months for months,
percent for %, etc. Note that fractional units
generally have a plural numerator and singular denominator.)*

*For both parts of this problem, be sure you can explain
what the practical meanings of the partial derivatives are.*