# Pure Maths 4

Past papers 18

… 到最後你要記（刻意背誦）的東西其實很少。即是好像小學生學生字一樣。一年級時所學的生字，到二年級時已經不是「生字」，而是「熟字」。所以，對於一個二年級學生來說，他只需要背誦二年級時所學的「生字」，而不是所有在一、二年級時所學的「生字」。

（LWT：現在我基本上打開本 pure maths（純數學）書，都不懂如何做內裡的題目。）

（LWT：如果是這樣說的話，即是我以後就溫那本 tip paper？）

（LWT：如果只溫 tip paper，會不會有些運算細節被忽略了？）

「Tip paper」這個方法，我初初發明它，主要是用來記錄大部分人常犯的錯誤，或者是自己常犯的錯誤。

— Me@2010.04.18

Always make new mistakes.

— Esther Dyson

Always make new mistakes.

Always make new mistakes.

— Me@2007

# Action at a distance

Functional programming 5

The essence of functional programming is that programs are built entirely of functions with no side effects that compute their results based solely on the values of their arguments. The advantage of the functional style is that it makes programs easier to understand. Eliminating side effects eliminates almost all possibilities for action at a distance.

— Peter Seibel

2010.04.18 Sunday ACHK

# Go West

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There where the air is free
we’ll be what we want to be
Now if we make a stand
we’ll find our promised land

— Go West

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2010.04.18 Sunday $ACHK$