Marginal product of labor shows the law of diminishing marginal returns. this implies that after MPL hits the zero, total product starts to be negative, where what we called negative diminishing marginal return. and Marginal cost curve is inversely related to marginal product of labor curve as above below. My question is, 1. when marginal product of labor starts to be negative at some point (it is below the x-axis, which is labor), we say negative marginal product of labor sets in, Does this necessary mean that, at corresponding point on the marginal cost curve, there will be a negative marginal product of labor? if yes, at which point on the marginal curve start to exhibit marginal product of labor corresponding to the point on the first graph? 2. we know the ATC and AVC curve looks like U-shape and Marginal cost curve falls and eventually rise, we can infer from this that two curves eventually meets and cross each other as both MC and ATC keep increasing, once the ATC curve lies above the Marginal cost, firms start to make negative econ profit. per Worker -Alc MPL Labour MC Cose