问题
填空题
设
|
答案
∵
，a
的夹角为钝角，∴b
•a
＜0且b
，a
不反向，b
即-3x-10＜0，解得x＞-
，10 3
当两个向量反向时，
=ka
，即b
，x=-3k -2=5k
解得x=
，6 5
∴当
，a
的夹角为钝角时，x＞-b
且x≠10 3 6 5
故答案为：x＞-
且x≠10 3 6 5
搜题请搜索小程序“爱下问搜题”
设
|
∵
，a
的夹角为钝角，∴b
•a
＜0且b
，a
不反向，b
即-3x-10＜0，解得x＞-
，10 3
当两个向量反向时，
=ka
，即b
，x=-3k -2=5k
解得x=
，6 5
∴当
，a
的夹角为钝角时，x＞-b
且x≠10 3 6 5
故答案为：x＞-
且x≠10 3 6 5
| 完形填空。 | ||||
| I have always been interested in clowns (小丑). The earliest thing I can remember, as a child of three, is seeing a pair of clowns-one very fat, and the other very 1 . A traveling circus (马戏团) came to our town and my parents took me to see it. When we arrived at the circus, everyone was laughing at the clowns. I didn't understand why they were laughing, 2 I laughed too. While I was 3 , the fat clown came and sat down next to me. "Shall we dance?" he asked, then 4 me up and began dancing. I felt frightened and began to cry. 5 then I have been interested in clowns. They make me laugh a lot, although they still make me a bit 6 too. In life, we sometimes laugh at things that 7 us. We often laugh most at people who make us nervous. When we laugh, we relax and 8 ourselves. People who never laugh can become worried and ill. Laughter is like medicine and a clown is like a 9 . There have always been, and there will always be clowns, because people need to laugh. Laughter is the best kind of 10 in life. | ||||
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