The production function for a firm is given by Q = LK, where Q denotes output; Land K labor and capital inputs. Wage rate and rental rate are given by w and r respectively.

(a) Show whether or not the above production function exhibits diminishing marginal productivity of labor.
(b) Determine the nature of the Return to Scale as exhibited by the above production function
(c) Using the Lagrangian Multiplier method, calculate the least cost combinations of labor and capital and the resulting long run total cost function for the above production function. Explain the economic significance of the Lagrangian Multiplier and calculate its value.
(d) Using the above cost function, calculate the numerical value of long run total cost when Q = 225, w = 16 and r = 144.