Find the partial derivative with respect to x : ∂ x ∂ ( 3 x 2 y 3 ) = 6 x y 3 .
Find the partial derivative with respect to y : ∂ y ∂ ( 3 x 2 y 3 ) = 9 x 2 y 2 .
The partial derivative with respect to x is 6 x y 3 .
The partial derivative with respect to y is 9 x 2 y 2 .
Explanation
Problem Analysis We are asked to find the partial derivative of the expression 3 x 2 y 3 . Since the problem does not specify with respect to which variable we should differentiate, we will find both partial derivatives: with respect to x and with respect to y .
Partial Derivative with Respect to x First, let's find the partial derivative with respect to x . We treat y as a constant. Using the power rule, we have: ∂ x ∂ ( 3 x 2 y 3 ) = 3 y 3 ∂ x ∂ ( x 2 ) = 3 y 3 ( 2 x ) = 6 x y 3
Partial Derivative with Respect to y Now, let's find the partial derivative with respect to y . We treat x as a constant. Using the power rule, we have: ∂ y ∂ ( 3 x 2 y 3 ) = 3 x 2 ∂ y ∂ ( y 3 ) = 3 x 2 ( 3 y 2 ) = 9 x 2 y 2
Final Answer Thus, the partial derivative with respect to x is 6 x y 3 and the partial derivative with respect to y is 9 x 2 y 2 .
Examples
Partial derivatives are used in economics to analyze marginal cost and marginal revenue. For example, if a company's cost function is given by C ( x , y ) = 3 x 2 y 3 , where x is the amount of labor and y is the amount of capital, then the partial derivative ∂ x ∂ C = 6 x y 3 represents the marginal cost of labor, and ∂ y ∂ C = 9 x 2 y 2 represents the marginal cost of capital. These partial derivatives help the company make decisions about how much labor and capital to use to minimize costs.
The partial derivative of f ( x , y ) = 3 x 2 y 3 with respect to x is 6 x y 3 and with respect to y is 9 x 2 y 2 .
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