The demand curve faced by a monopolist is negatively sloped.
In a monopoly, the firm has control over the entire market for its product or service, which means that it can influence the price of the product by adjusting the quantity supplied. The monopolist faces the entire market demand curve for its product, which shows the relationship between the price of the product and the quantity that consumers are willing to buy at that price.
The demand curve for a monopolist is negatively sloped because as the monopolist increases the price of its product, consumers are willing to buy less of it. This is because the monopolist is the only supplier of the product, so consumers do not have the option to buy a substitute product at a lower price. Therefore, the monopolist has some pricing power, but it is limited by the demand curve for its product.
In contrast, a perfectly competitive firm faces a horizontal demand curve because it is a price taker - it must accept the market price for its product and cannot influence the price by adjusting the quantity supplied.