In the short run, if a firm in a perfectly competitive market is producing at the point at which price exceeds marginal cost, the firm: should not change its output level. is maximizing its profits. should increase its output. should decrease its output.

When a company produces and sells x thousand units per week, its total weekly profit is p thousand dollars, where upper p equals startfraction 800 x over 100 plus x squared endfraction . the production level at t weeks from the present is x equals 4 plus 2 t. find the marginal profit, startfraction dp over dx endfraction and the time rate of change of profit, startfraction dp over dt endfraction . how fast (with respect of time) are profits changing when tequals8?