## Archive for 九月, 2007

2007/09/29

2007/09/26

2007/09/22

2007/09/21

2007/09/17

2007/09/15

2007/09/10

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### Math Joke

2007/09/09

Before learning calculus, I know that fact that $\frac{d}{dx} x = 1$. Some body asked $\frac{d}{dx} x*x$, my deduction is $\frac{d}{dx} x*x = \frac{1}{x} x*x = x$.

There are a lot more.