已知a→=3,b→=5，且a→+λb→与a→-λb→垂直，则λ等于( )_刷题宝

题干

已知a→=3,b→=5，且a→+λb→与a→-λb→垂直，则λ等于( )

A： $\frac{3}{5}$

B：± $\frac{3}{5}$

C：± $\frac{4}{5}$

D：± $\frac{9}{25}$

上一题下一题 0.0难度选择题更新时间:2016-12-13 06:18:51

答案(点此获取答案解析）

B

同类题1

完形填空

People all over the world eat rice. 1 people in Asia (亚洲), Africa (非洲) and South America 2 it every day of their lives. Some people almost don't eat 3 except rice.

Rice is a kind of 4. There are more than 7, 000 kinds of rice. Most kinds are water plants. Farmers 5rice in many countries even in the southern part of Russia and in eastern Australia.

No one really knows where rice 6. Someone in China wrote about it almost 5,000 years ago. Some scientists (科学家) think that rice 7 in West Africa first, but 8 think it 9from India and then was 10to other parts of the world.

同类题2

如果执行程序框图，那么输出的S等于（）

同类题3

有人说英国资产阶级革命实际上是议会的变革，“革命前是国王的议会，革命后是议会的国王”。这表明（）

同类题4

我市有着丰富的旅游资源，其中道县温泉吸引了八方游客，此温泉属硅酸盐矿泉，主要含有硅酸钠（化学式为：Na₂SiO₃），则Na₂SiO₃中硅元素的化合价为（　　）

同类题5

下列叙述正确的是( )

小学学科试题库

初中学科试题库

高中学科试题库