As long as marginal utility is positive, total utility must be

As long as marginal utility is positive, total utility must be increasing. Total utility is the overall amount of satisfaction or happiness that a person derives from consuming a certain amount of a product or service. Marginal utility, on the other hand, refers to the additional satisfaction that a person gains from consuming one more unit of the same product or service. If marginal utility is positive, it means that the additional satisfaction gained from consuming one more unit of the product is positive. This implies that the consumer's overall level of satisfaction is increasing as they consume more of the product. As a result, the total utility must also be increasing as the consumer consumes more of the product. Conversely, if the marginal utility is negative, it means that the additional satisfaction gained from consuming one more unit of the product is negative, which indicates that the consumer's overall satisfaction is decreasing as they consume more of the product. Therefore, as long as marginal utility is positive, the total utility must be increasing.