作者hahahappyyo (haha)
看板trans_math
标题[考古] 99台大A-5
时间Thu Jun 16 13:59:12 2011
请问这样解是正确的吗?
5.Let D be the region bounded by the curve C:x=t^3+t^2 y=t^2+t 0<t<1
and the line y=x.
Find the area of D.
<sol>
by Green's Thm,
1 31
─∫(xdy-ydx) = -─
2 C 60
1 1
and ─x1x1 = ─
2 2
31 1 1
so ─ - ─ = ─
60 2 60
我没有答案 所以也不知道对不对= =
可是总觉得有点怪怪的
谢谢:)
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※ 发信站: 批踢踢实业坊(ptt.cc)
◆ From: 114.44.23.3
1F：推 batata:答案 -121/60 我看王博解答的140.116.104.172 06/16 23:37
2F：→ alasa15:area不会是负数吧 118.169.1.60 06/17 01:09
3F：→ alasa15:#1D18J6WX 或你直接搜寻A也找的到 118.169.1.60 06/17 01:14
4F：→ hahahappyyo:答案负的就怪怪的耶 114.42.233.194 06/17 13:30
5F：→ hahahappyyo:我找到那篇了感谢你:D 可是有点无法理 114.42.233.194 06/17 13:31
6F：→ hahahappyyo:解第二行∫ (t - t^3)(3t^2 + 2t)dt 114.42.233.194 06/17 13:31
7F：→ hahahappyyo:是代入甚麽的 114.42.233.194 06/17 13:31
8F：推 rygb:x =x(t) dx=?dt dy=?dt y=y(t) 带入 114.34.122.244 06/17 16:36