For monopolies, marginal price curves are upward sloping and marginal revenues are downward sloping.
The marginal income curve for the monopoly company lies beneath its demand curve. It indicates the extra income received from promoting an additional unit.
The usual shape of a marginal income curve for a monopolist is downward sloping as the addition of each additional unit will enlarge the output which will reduce the charge of the output. The inverse relation between the charge of a output and its quantity shows the downward sloping nature of the curve.
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