求助啊,谁能回答这个问题

懿囦

求助各位了.第二题怎么解答?在此谢谢了

jeffnz

关键部分被skykiwi的水印遮住了。。。

我就先去睡了。。

ryantao2010

目测是253级别的

懿囦

jeffnz 发表于 2012-10-3 21:33
关键部分被skykiwi的水印遮住了。。。

我就先去睡了。。

the question is :find the volume obtained when the shaded region is rotated through 360 about the x-axis. firstly,Thank you for the reply.

jeffnz

懿囦 发表于 2012-10-3 23:19
the question is :find the volume obtained when the shaded region is rotated through 360 about the  ...

its easy.

Get the volume for the whole area under AB line.

The white bit can be obtained by calculating the area under that AB curve.

Then convert that white area into volume.

Subtract the whole volume with the white bit volume and its done!

懿囦

jeffnz 发表于 2012-10-4 16:51
its easy.

Get the volume for the whole area under AB line.

thank you so much

mml

disk method吧好象叫。切成一片一片的，每片的面积是大圆-小圆，然后沿x axis做积分
从0到5

mml