The cyclist's power to climb is 0 watts (W).
To find the power a cyclist must exert to climb a hill, we need to consider the work done against gravity.
Power is defined as the rate at which work is done, and work can be calculated as the force applied multiplied by the distance traveled. In this case, the force is the component of the cyclist's weight parallel to the hill, and the distance is the height of the hill.
The formula for power is P = W/t, where P is power, W is work, and t is time.
In this scenario, the cyclist is coasting down the hill, so no work is done against gravity.
Therefore, the cyclist's power to climb is 0 watts (W).