一道外国的大学数学题,麻烦帮下忙,明天需要用到,麻烦帮帮忙,

Question

一道外国的大学数学题,麻烦帮下忙,
明天需要用到,麻烦帮帮忙,

Answer 1

At x meters (x in [0,4]),the area of cross section is πr²
When the length is dx meters,the volume is πr²dx m³,the mass is ρ(x)πr²dx
See picture for the rest:




不小心漏了0.01π,结果应当乘以0.01π