Uh oh! Wolfram|Alpha doesn't run without JavaScript.
Please enable JavaScript. If you don't know how, you can find instructions
here
.
Once you've done that, refresh this page to start using Wolfram|Alpha.
在疫情中,新增病例的峰值出现在累计病例曲线 f(t) 的拐点。用几何和 f'' 说明。
在疫情中,新增病例的峰值出现在累计病例曲线 f(t) 的拐点。用几何和 f'' 说明。
Natural Language
Math Input
Extended Keyboard