Find the volume generated when an arc of the
curve of y=x³ rotates round the y-axis
between x=0 and x=2.
1 integration Q
2012-03-27 1:43 am
回答 (3)
2012-03-30 1:50 am
There's nothing in y=0以下既位 ...
2012-03-29 17:50:14 補充：
There's nothing in y=0以下既位...
2012-03-29 17:50:14 補充：
There's nothing in y=0以下既位...
2012-03-27 9:59 am
mfmartinfan :
應該001個位答得岩啵~如果好似你咁做
你係會計左下面個volume~
我用disc method都係計到001既ans
2012-03-28 19:04:14 補充：
你咁講..佢話x由0~2,咁y=0以下既位呢?
你而家淨係計左y=0上面既位;
而y=0下面係計唔到= =
應該001個位答得岩啵~如果好似你咁做
你係會計左下面個volume~
我用disc method都係計到001既ans
2012-03-28 19:04:14 補充：
你咁講..佢話x由0~2,咁y=0以下既位呢?
你而家淨係計左y=0上面既位;
而y=0下面係計唔到= =
2012-03-27 5:28 am
For calculating volume, there are 2 methods,
"disc method" and "shell method". In this question, using "shell method" is better.
∫2πxy dx . . . (from 0 to 2)
= 2π∫x^4 dx
= (2/5)πx^5
= 64π/5 (unit^3)
2012-03-27 11:54:57 補充：
可能係啩, 我覺得題目係要求 "rotates round the y-axis between x=0 and x=2",
即係貼 x-axis 果 part, 你係講緊貼 y-axis 果 part 囉.
"disc method" and "shell method". In this question, using "shell method" is better.
∫2πxy dx . . . (from 0 to 2)
= 2π∫x^4 dx
= (2/5)πx^5
= 64π/5 (unit^3)
2012-03-27 11:54:57 補充：
可能係啩, 我覺得題目係要求 "rotates round the y-axis between x=0 and x=2",
即係貼 x-axis 果 part, 你係講緊貼 y-axis 果 part 囉.
收錄日期: 2021-04-13 18:35:29
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