Sketch LTC, LAC, and LMC curves for the production function Q = 3 K L where r = 3 and w = 2.

Hint: A good way to approach it is to use the method of Lagrange multipliers to find the cost minimizing employment of K, and L, as a function of output Q. Once you have these optimal employment levels as functions of Q, you can easily find the LTC function, and then you can find the LAC and LMC functions from it.

b. (1.0 points) Does this production function have constant, increasing, or decreasing returns to scale?