问题
填空题
已知向量
|
答案
∵k
+a
与b
-3a
垂直，b
∴(k
+a
)•(b
-3a
)=0b
化简可得k
2+(1-3k)a
•a
-3b
2=0，b
代入可得5k+（1-3k）
•5
•13
-3×13=065 65
化简可得解得k=19
故答案为：19
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已知向量
|
∵k
+a
与b
-3a
垂直，b
∴(k
+a
)•(b
-3a
)=0b
化简可得k
2+(1-3k)a
•a
-3b
2=0，b
代入可得5k+（1-3k）
•5
•13
-3×13=065 65
化简可得解得k=19
故答案为：19
| 完形填空。 | |||
| What is a museum? A museum is a good place to keep 1 and beautiful things. A museum may be a place to learn about science. A museum can be a place 2 art of humans or animals. What is inside a museum? Some museums 3 old cars and airplanes. 4 museums have pictures and sculptures. Others have rocks and old bones. One museum even has 5 coal mine inside! Many cities have museums. Some very small 6 have museums, 7 . Indianapolis has a 8 museum. Children do not have to 9 to get in. Children often go to the museum. They like to see at the dinosaur bones. They see a white bear ten feel tall. They go inside an old log cabin(小木屋). On Saturday, Indianapolis children can 10 talks about animals and trees. | |||
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