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標題: pure maths help [打印本頁]

作者: ktsss113 時間: 2011-5-17 11:24 PM 標題: pure maths help

show that r = RH / (h^2-2RH)^(1/2)

作者: ktsss113 時間: 2011-5-17 11:25 PM

問題在在這,thanks for all help

作者: Sprite_Zero 時間: 2011-5-18 01:21 AM

Construct angle x as shown.
tan x = r/h, cot x = h/r
sin x = R/(R - h), csc x = (R - h)/R

Using the formula 1 + (cot x)^2 = (csc x)^2,
1 + (h/r)^2 = [(R - h)/R]^2

By solving the result can be obtained.

作者: 11AL考生 時間: 2011-5-18 01:30 AM

根本唔係pure
我用｢不是定理｣做
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