推 how155031 :感謝你!! 12/02 20:06
※ 引述《how155031 (cow)》之銘言：
: http://miupix.cc/pm-L32LAC
: 麻煩了，謝謝
: 字醜請見諒
所求的是第一卦限內的範圍 故 z = 1-y^2≧0 即 y≦1
因此這塊體積在 xy 平面上的範圍是以 y = 0, y = 1, y = 2x, x = 3 包住的
也就是這樣的一個範圍:
y
^
1| _______
| / |
|/ |
+------------>x
3
1 3
因此所求體積即為 ∫ ∫ 1-y^2 dx dy 計算過程略 答案是 15/8
0 y/2
--
'You've sort of made up for it tonight,' said Harry. 'Getting the
sword. Finishing the Horcrux. Saving my life.'
'That makes me sound a lot cooler then I was,' Ron mumbled.
'Stuff like that always sounds cooler then it really was,' said
Harry. 'I've been trying to tell you that for years.'
-- Harry Potter and the Deathly Hollows, P.308
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