皮皮学，免费搜题
登录
搜题
【简答题】
已知a、b是非零向量，指出下列等式成立的条件： ①|a|+|b|=|a+b|成立的条件是______； ②|a|+|b|=|a-b|成立的条件是______； ③|a+b|=|a-b|成立的条件是______； ④|a|-|b|=|a-b|成立的条件是______．
手机使用
分享
复制链接
新浪微博
分享QQ
微信扫一扫
反馈参考答案：
举一反三
【单选题】What word is wrong in this sentence? There has been a lot of problems at my work lately, but we have been dealing with them.
A.
has
B.
lot
C.
problems
D.
work
E.
have
F.
them
【单选题】听力原文： There have been many great inventions, things that changed the way we live. The first great invention was one that is still very important today—the wheel. For hundreds of years after that there...
A.
In the early 1800's.
B.
In the late 1800's.
C.
In the second half of the 19th century.
D.
In the first part of the 20th century.
【简答题】A; Susan,any plans for tomorrow? B;Yeah, 16 A;How exciting ! B;It’s a rock music concert 17 A;No ,it’s too noisy for me .Thank you anyway. B; 18 A;I like country music. B;Really? I know there’s a coun...
【单选题】听力原文： There have been many great inventions, things that changed the way we live. The first great invention was one that is still very important today -- the wheel. This is used in cars, trucks, and t...
A.
The tractor.
B.
The ear.
C.
The wheel.
D.
The steam engine.
【单选题】听力原文： There have been many great inventions, things that change the way we live. The first great invention was one that is still very important today—the wheel. This made it easier to carry heavy thin...
A.
In the second half of the 19th century.
B.
In the 1960s.
C.
In the first half of the 20th century.
D.
In the early 1800s.
【简答题】2017河南中考阅读理解C The idea that red means stop and green means has influenced our lives in more ways than just traffic signals(信号).We have been taught from a young age that the color red means er and ...
【简答题】____ n. the natural home of a plant or animal
相关题目：
参考解析：
知识点：
题目纠错 0
发布
