Suppose the production function is f(z₁, z₂) = z₁²z₂²

4.1 Find the cost function for this firm. Does it exhibit increasing or decreasing or constant returns to scale? Find the first-order condition for maximizing pq C(q), and find and evaluate the second-order condition.

4.2 We often hear that "Increasing returns are inconsistent with perfect competition." Evaluate this statement given your answer to 4.1.