Incorrect monotonicity analysis

[Haohao123coding]

Describe the bug
The calculator analysed a wrong monotonicity of function $y = x - \lfloor 0.9x \rfloor$.

Steps To Reproduce

Steps to reproduce the behavior:

1. Go to plot mode.
2. Add a function $y = x - \lfloor 0.9x \rfloor$.
3. Click the analyse button.
4. Check "monotonicity"
5. See error.

Expected behavior
No monotonicity.

Device and Application Information

• OS Build: Windows 11 build 26200.7623
• Architecture: AMD64
• Application Version: 11.258.4.0
• Region: China Mainland
• Dev Version Installed: False

Requested Assignment
I'm just reporting this problem. I don't want to fix it.

[Haohao123coding]