Final answer:
A partial derivative measures how a function changes with respect to one variable while holding the other variables constant. It is useful in many areas of mathematics and science, such as optimization, physics, and economics.
Step-by-step explanation:
A partial derivative measures how a function changes with respect to one variable while holding the other variables constant. It is useful in many areas of mathematics and science, such as optimization, physics, and economics. By finding the partial derivative of a function with respect to each variable, we can determine how the function changes as each individual variable changes, which is helpful in understanding the behavior of the function and solving problems.