Background\text{Background}Background Last night, lots of students from primary school came to our class to study OI.\text{Last night, lots of students from primary school came to our class to study OI.}Last night, lots of students from primary schoo
A video by 3Blue1Brown in Bilibili\text{A video by 3Blue1Brown in Bilibili}A video by 3Blue1Brown in Bilibili I don't have a systematic face to Derivatives before, but now I do.\text{I don't have a systematic face to Derivatives before, but now I do.