Forgot password
 Register account
View 20|Reply 4

[不等式] 已知$a^2+b≥0,a^2-b≤0$,能推导出$a=0,b=0$吗

[Copy link]
走走看看 posted 2025-7-19 11:50 |Read mode
已知$a^2+b≥0,a^2-b≤0$,能推导出$a=0,b=0$吗

有个老师在抖音视频中,给出以上的推论,但没有给出过程。

我也推导了下,总觉得这个推论不怎么对。

24

Threads

1016

Posts

46

Reputation

Show all posts

战巡 posted 2025-7-19 11:58
明摆着不能,只能推出$b>a^2\ge 0$
随便举个反例:$a=1,b=2$

0

Threads

6

Posts

1

Reputation

Show all posts

老司機 posted 2025-7-19 11:58 from mobile
a=1, b=2
original poster 走走看看 posted 2025-7-19 12:34
Last edited by 走走看看 2025-7-19 15:32b≥-a²,b≥a²,只能得出b≥a²≥0。
original poster 走走看看 posted 2025-7-19 15:28
战巡 发表于 2025-7-19 11:58
明摆着不能,只能推出$b>a^2\ge 0$
随便举个反例:$a=1,b=2$
b=a²也满足吧?

Quick Reply

Advanced Mode
B Color Image Link Quote Code Smilies
You have to log in before you can reply Login | Register account

$\LaTeX$ formula tutorial

Mobile version

2025-7-19 19:38 GMT+8

Powered by Discuz!

Processed in 0.014034 seconds, 23 queries