Quod Erat Demonstrandum

2015/10/15

二次和是和

Filed under: Fun,NSS — johnmayhk @ 5:43 下午

觀察

1^2+1^2=1+1

1.2^2+0.6^2=1.2+0.6

1.2^2+0.4^2=1.2+0.4

還有沒有其他例子,滿足以下關係?

x^2+y^2=x+y ……………… (*)

學過 (more…)

廣告

2015/10/11

正四面體,兩個夾角

Filed under: Fun — johnmayhk @ 9:10 下午
Tags: ,

1.一個玩具

早前入了些貨,其中一件:

正四面體困在籠中,

硬闖不能:

如何逃脫? (more…)

2015/10/07

三角題

Filed under: NSS — johnmayhk @ 2:58 下午
Tags:

Just come across a part of a core mathematics trigonometry problem today morning, I and my student used different ways to solve it, but actually, same results turn up:

johnmayhk-trigonometry

Given

AC=b,

CB=a, where a > b

\angle CAB=\theta < 90^o,

find c in terms of a,b,\theta.

(Note: this is an ‘A.S.S.’ given, but the triangle can be uniquely determined.)

Method 1 (more…)

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