4. (40 points) Consider another rm with the following production function f(Ka L) : { 1 3% Basically, the rm experiences the constant return to scale (CBS) in the rst i} units of production and then decreasing return to scale (DRS) after that. This is actually the reality of how rm usually makes zero prot in the rst phase of being in business and then starts making prot later, given that there are no entrants into the market. (a) (20 points) Using the cost minimization method, calculate the optimal level of labor 1;\" and capital K\" and the minimal total cost. Your answers should be a function of wage w, cost of capital 1' and output level 3}. (b) (20 points) If wage to = 8 and cost of capital 1" = 4, at what level of output and price will this rm switch to having CR3 production function to having DRS production function