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Math Help - need help please!

  1. #1
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    need help please!

    If a car's velocity is given by v(t) = t + 25 miles per hour, how far has the car traveled between the times t = 1 hour and t = 3 hours
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  2. #2
    Forum Admin topsquark's Avatar
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    Quote Originally Posted by bobby77
    If a car's velocity is given by v(t) = t + 25 miles per hour, how far has the car traveled between the times t = 1 hour and t = 3 hours
    Not exactly sure what you are asking.
    v(1) = 26 mph
    v(3) = 28 mph
    So the car is moving between 26 and 28 mph during the times t = 1 hr and t = 3 hr.

    Was that what you were looking for? The only other thing I can think of is that you are looking for an average speed which would be \frac{26+28}{2}=27 \, mph since v is a linear function of t.

    -Dan
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  3. #3
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    s=\int|v|dt, but since the velocity function isn't negative on your interval you can drop the absolute value brackets. So the total distance traveled is \int_{1}^{3}t+25dt=54miles
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  4. #4
    Forum Admin topsquark's Avatar
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    (Sigh). I hate it when I read the question wrong!

    -Dan
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  5. #5
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    It happens to the best of us. I wish I could say that was the reason I can't answer a question correctly.
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