Application of differentiatio

2013-01-06 5:51 am
1.A balloon is rising at a constant speed of 7 ft/sec. A boy is cycling along a straight road at a speed of 10 ft/sec. When he passes under the balloon, it is 45 ft above him. How fast is the distance between the boy and the balloon increasing 3sec later?
2.A container in the shape of an inverted cone has height 16cm and radius 5cm at the top. It is partially filled with liquid that oozes through the sides at a rate proportional to the area of the container that is in contact with the liquid. If we pour the liquid into the container at a rate of 2cm^3/min, then the height of the liquid decreases at a rate of 0.3cm/min when the height is 10cm.

If we want to keep the liquid at a constant height of 10cm, at what rate should we pour the liquid into the container?

回答 (1)

2013-01-06 6:48 pm
✔ 最佳答案
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圖片參考:http://i1090.photobucket.com/albums/i376/Nelson_Yu/int-626.jpg


圖片參考:http://i1090.photobucket.com/albums/i376/Nelson_Yu/int-2354.jpg


2013-01-06 19:42:05 補充:
http://i1090.photobucket.com/albums/i376/Nelson_Yu/int-626.jpg
http://i1090.photobucket.com/albums/i376/Nelson_Yu/int-2354.jpg


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