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ÊÁѤÃÊÁÒªÔ¡ | ¤ÙèÁ×Í¡ÒÃãªé | ÃÒª×èÍÊÁÒªÔ¡ | »¯Ô·Ô¹ | ¢éͤÇÒÁÇѹ¹Õé | ¤é¹ËÒ |
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à¤Ã×èͧÁ×ͧ͢ËÑÇ¢éÍ | ¤é¹ËÒã¹ËÑÇ¢é͹Õé |
#1
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µÃÕ⡳ (cot 25-1)...(cot 20-1)
¨§ËÒ¤èҢͧ (cot 25⋅ −1)(cot 24⋅ −1)(cot 23⋅ −1)(cot 22⋅ −1)(cot 21⋅ −1)(cot 20⋅ −1)
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#2
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ÍéÒ§ÍÔ§:
$(\cot A - 1)(\cot (\frac{\pi}{4}-A)-1) = 2$ |
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