We must first understand that discrete domain refers to the existence of values that cannot be taken within an established range and as a continuous domain to those whose values can be taken in their entirety without any restriction.
The funtion y=650x has as domain all values of x including zero (value where the climbing begins) but it should be understood that it will not be all hours continuously climbing, there are periods of time where you must stop to rest, so
Dm={∀x/x∈〖IR〗^+∪{0}-t} this is for all real positive numbers including zero
minus t where t represents the values that at the discretion are taken by the trainer or the climber for rest
