?? f (x) ? g (x) ??????????????????
...????????????????????????????? 6. ????????????????f (x)?g (x)???T????????????????????????0?????????T??????????????????...
https://www.zhihu.com/question/65884679
Var?AX?=AVar?X?A?????? - ??
...3?????? cov (AX)=E [ (AX-E (AX)) (AX-E (AX))^T]=E [ (AX-E (AX)) ( (AX)^T-E (AX)^T)]=E [ (AX-E (AX)) (X^TA^T-E (AX)^T)]=E [ (AX-AE (X)) (X^TA^T- (AE (X))^T)]=E [ (AX-AE (X)) (X^TA^T-E (X)^TA^T)]=E [A (X-E (X)) (X^T-E (X)^T)A^T]=AE [ (X-E (X)) (X^T-E (X)^T)]A^T=AE [ (X-E (X)) (X-E (X))^T]A^T=Acov (X)A^T...
https://www.zhihu.com/question/51082135
e?x???????????_????
...e?x??????????? y??e?x???????????????????x?R?y>0??y?????0,1???????X????????????X?????????????1???????????????...
https://zhidao.baidu.com/question/391959772.html
???Word???????????x???_????
...???Word???????????x?? ? ?word2016???????????1?????word??????????????2??????3???????????4??????????5??????????????...
https://zhidao.baidu.com/question/1887600033410736428.html
Y ???? X ???????????????????????? - ??
...Y?????????X??????????3?????????????????????????????? ???????????????????????????????X????????????...
https://www.zhihu.com/question/30060763
x^x^x??????? - ??
...x^x^x????????????...
https://www.zhihu.com/question/454624170
x' ??????x prime ?prime?????? - ??
...???20?????x? ??? x prime ??????? x ??????prime ?????????x??x? ("x second") ?x? ("x third") ????????prime????????? ???1950???1960??????prime??????????????...
https://www.zhihu.com/question/430355710
[x]????????????. - ????
...?????x???????x???????? [x]?INT (x)? ??????????????????? {x},??? {x} =x- [x]? ? [x]+1>x? [x]????1> {x}?0??????x= [x],??? {x}=0? ??????????????????????? {x}???? [x]? ......
https://zhidao.baidu.com/question/524580000175725245.html
yandex???? yandex???? - ????
...yandex???? yandex????Yandex?????????????https://www.yandex.com/ ?????????????????? ......
https://zhidao.baidu.com/question/1618348495286222947.html
x^x ??????? - ??
...??????????????????????????????? 2011 ? 1 ??????????????????????????????????????????????????????????????????????????????????????????????? ......
https://www.zhihu.com/question/407450664