A firm produces a quantity Q of breakfast cereal using labor L and material M with the

Question:

A firm produces a quantity Q of breakfast cereal using labor L and material M with the production function Q = 50ˆšML + M+ L. The marginal product functions for this production function are

a) Are the returns to scale increasing, constant, or decreasing for this production function?
b) Is the marginal product of labor ever diminishing for this production function? If so, when? Is it ever negative, and if so, when?