[DSE 2020] 同學仔開始溫你嘅 數學 未？

請出手
b題嚟
但我信你地唔洗a題啦

int from 0 to pi/6 of cos(x^2) dx
>= int from 0 to pi/6 of cos(x) dx = 1/2

屌 直接秒左
a題就係要你証係
cosx<=cosx^2 for 0<=x<=1

主要我想睇會唔會有其他方法
所以就唔比a題

其他方法我就諗唔到
a part證明:
x >= x^2 for any 0<=x<=1
since cos(x) is decreasing on (0,1)
cos(x) <= cos(x^2) for any 0<=x<=1

都勁架啦 冇hints都知佢想點玩
我直接睇B題完全諗唔到
心諗係咪因為我日日走堂 所以佢教左啲我唔識嘅嘢
望完A題就明咩事了

唔知有冇錯區
想問下estimate mean既estimator( Ybar=1/n summationYi)呢個係咪一個unbiased但not consistent既estimator?

yes

有咁麻煩架咩 印象中冇咁麻煩

點解會not consistent

咁population mean呢?

population mean 算 estimator 嗎?

係喎.... 咁姐係sample mean係一個ubiased+consistent estimator?

睇下咩context
不過多數都係

唔知邊年嘅final嚟

有冇邊個context係unbiased+inconsistent?
例如我用X~N(M,sigma^2) 用X1去estimate個mean就係unbiased 但係就not consistent? 咁樣叫唔叫係?

X1的確係unbiased not consistent
至於 sample mean
我會話佢consistent係因為LLN
但諗到如果有啲case係特別到連LLN都唔成立嘅話…
都係戴返個頭盔先啫

係咪淨係可以由probi去determine個estimator係咪consistent?

唔係好明你咩意思

https://lihkg.com/thread/1879550/page/1
#456

中大year1 engine 要讀嘅嘢會唔會太誇張
Multivariable Calculus 唔係正常係year2讀咩

都係一啲以前AL會讀嘅嘢咋喎
Multivariable Calculus 仲以為會見到啲 partial differentiation multiple integration 添
可能未到戲肉

40幾個local加埋我等緊你救
我估唔到當我學校仲係到教緊Fundamental theorem of calculus嘅時候
我嘅同年人(DSE應該低分過我 仲要未必讀過M1 M2)
居然學緊Multivariable Calculus

如果私補嘅話唔知收幾錢好呢
利申：唔識

15個口罩一堂啦

https://lihkg.com/thread/1088395/page/5
有無人有down到份paper2
原來上年miss左個咁好玩既post