※ 引述《mary320570 (mary320570)》之銘言：
: 1請問d選項是這樣列式嗎，謝謝
: http://i.imgur.com/TrscPK0.jpg
u = x - 1
f(x) = x^2
f(u) = (u + 1)^2
1
∫2πuf(u)du
0
= 2π∫u(u^2 + 2u + 1)du
1
= 2π[(1/4)u^4 + (2/3)u^3 + (1/2)u^2]|
0
= 2π[(1/4) + (2/3) + (1/2)]
= (17/6)π
--
※ 發信站: 批踢踢實業坊(ptt.cc), 來自: 61.56.10.112
※ 文章網址: https://www.ptt.cc/bbs/Math/M.1483667910.A.466.html