Over what interval of time in minutes was the jogger heart rate changing at the constant rate
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We have a graph of the heart rate vs time.
We want to find on what interval the heart rate increases with a constant rate.
That interval is 3min ≤ t ≤ 4 min
The general function that increases with a constant rate is the general linear function:
y = a*x + b
Where a is the slope and also defines the constant rate of change.
Then the interval where the jogger heart rate changes at a constant rate is the part where we have a linear function (not the horizontal line, there the heart rate does not change).
Then the interval where the heart rate changes with a constant rate is:
3min ≤ t ≤ 4 min
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