please show how its done for these questions.

A manufacturer of widgets has determined that the production function for a weekly production of p thousand gross of widgets is p = 1000 + 201-13 -513 - 314, where I is the number of labor hours per week in thousands and & is the amount of capital in thousands of dollars per week. Determine both of the marginal productivity functions with respect to labour and capital. The Cobb-Douglas production function for a company is given by P= 201 1/-148, where P is the monthly production value when k is the amount of the company's capital investment (in dollars per month) and / is the size of the labor force (in work hours per month). Find the marginal productivity functions with respect to labour and capital and the appropriate economic interpretations