[問題] 數學JJ#61
61. x^2+2y^2+5X-35的最大值，已知x^2+y^2=5
A.22 B.20 C.0 D.-20 E.-22
解答: D
X^2+2y^2+5X-35
= x^2+y^2+ y^2+5X-35
= 5+ y^2+5X-35
=-x^2+5x-25
=-(x-5/2)^2-18.75
x^2+y^2=5,x定义域【-√5,√5 】
最后的数是-18.82，所以选D
問題：看不懂定義域那邊....
--
※ 發信站: 批踢踢實業坊(ptt.cc)
◆ From: 174.1.45.169
推
10/03 15:07, , 1F
10/03 15:07, 1F
→
10/03 15:08, , 2F
10/03 15:08, 2F
→
10/04 02:04, , 3F
10/04 02:04, 3F
→
10/04 12:25, , 4F
10/04 12:25, 4F
推
10/04 14:01, , 5F
10/04 14:01, 5F
→
10/05 06:56, , 6F
10/05 06:56, 6F
GMAT 近期熱門文章
PTT職涯區 即時熱門文章
