
作者: PurpoolPoolObservatory
冬季清晨
新的秘境
冬季的深圳
好奇小子
小城松潘










sympy求偏导
In [1]: from sympy import symbols, log, diff
In [2]: a,b,c,v,t = symbols("a b c v t",real=True)
In [3]: u=a*log((b/a)*t+1)+c+v*t
In [4]: print(diff(u,t))
b/(1 + b*t/a) + v
centos7 支持exfat
https://linuxize.com/post/how-to-mount-an-exfat-drive-on-centos-7/
sudo yum install epel-release
sudo rpm -v --import http://li.nux.ro/download/nux/RPM-GPG-KEY-nux.ro
sudo rpm -Uvh http://li.nux.ro/download/nux/dextop/el7/x86_64/nux-dextop-release-0-5.el7.nux.noarch.rpm
sudo yum install exfat-utils fuse-exfat
sudo mount -t exfat /dev/xxxx /mnt/xxxx
大理风光
互动童谣6
和孩子一起划拳,边比划边念
先出铜坨(比划“石头”),
二出布(比划“布”),
三幺幺(大拇指和小拇指伸出,其他指头弯曲),
四剪刀(比划“剪刀”),
五六零(比划“零”),
砍三筒(在孩子手臂上轻点三下)。










