A firm's total cost function is given by the equation: TC = 4 000 + 12Q + 10Q 5.1 Write an expression for each of the following cost concepts: 5.1.1 Total fixed cost 4000 5.1.2 Total variable cost 0 + 1002 5.1.3 Average variable cost 5.1.4 Average total cost 5.1.5 Marginal cost Determine the quantity that minimises average total cost. Explain the relationship between marginal and average cost 5.2 5.3