#1
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µÃÕ⡳¤ÃѺ
1.$A+B=\frac{\pi}{2}$ , $\Big(cos(2A)+cos(B) \Big)^2+\Big(sin(2A)+sin(2B) \Big)^2=3$ $,A\leqslant B$ ËÒ¤èҢͧ $tan(3A)$
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Hope is what makes us strong. It's why we are here. It is what we fight with when all else is lost. |
#2
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à»ç¹ $B$ ËÃ×Í $2B$ ¨´ÁÒ¶Ù¡¨ÃÔ§æËÃ×Íà»ÅèÒ
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#3
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¹èҨж١¤ÃѺ ¼Á¾ÂÒÂÒÁÍÂÙèÂѧäÁèÍÍ¡àÅ 55 ¾Í´Õà¾×è͹½Ò¡¶ÒÁ¤ÃѺ
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Hope is what makes us strong. It's why we are here. It is what we fight with when all else is lost. 10 Á¡ÃÒ¤Á 2015 12:31 : ¢éͤÇÒÁ¹Õé¶Ù¡á¡éä¢áÅéÇ 1 ¤ÃÑé§, ¤ÃÑé§ÅèÒÊØ´â´Â¤Ø³ FranceZii Siriseth |
#4
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¼ÁµÔ´µÃ§¤èÒ $\sin A$
$\Big(cos(2A)+cos(B) \Big)^2+\Big(sin(2A)+sin(2B) \Big)^2=3$ $\sin(2A)+\sin(2B)=2\cos (A-B)=2\cos (2A-\frac{\pi}{2} )=2\sin 2A$ $(\cos(2A)+\cos(B))^2=(\cos(2A)+\sin(A))^2$ $=\cos^2 2A+2\cos 2A \sin A+\sin^2 A$ $\Big(cos(2A)+cos(B) \Big)^2+\Big(sin(2A)+sin(2B) \Big)^2=(\cos^2 2A+2\cos 2A \sin A+\sin^2 A)+4\sin^2 2A=3$ $3\sin^2 2A+2(1-2\sin^2 A) \sin A+\sin^2 A=2$ $3(2\sin A \cos A)^2+2\sin A-4\sin^3 A+\sin^2 A-2=0$ $12\sin^2A(1-\sin^2 A)+2\sin A-4\sin^3 A+\sin^2 A-2=0$ $-12\sin^4A-4\sin^3 A+13\sin^2A+2\sin A-2=0$ $12\sin^4A+4\sin^3 A-13\sin^2A-2\sin A+2=0$ $(2\sin A+1)(6\sin^3 A-\sin^2A-6\sin A+2)=0$ $\sin A =-\frac{1}{2} $ áÊ´§ÇèÒ $A$ à»ç¹ÁØÁã¹ $Q_3$ ËÃ×Í $Q_4$
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"¶éÒàÃÒÅéÁºèÍÂæ ã¹·ÕèÊØ´àÃÒ¨ÐÃÙéÇèÒ¶éÒ¨ÐÅéÁ ÅéÁ·èÒä˹¨Ðà¨çº¹éÍ·ÕèÊØ´ áÅÐÃÙéÍÕ¡ÇèÒµèÍä»·ÓÂѧ䧨ÐäÁèãËéÅéÁÍÕ¡ ´Ñ§¹Ñ鹨§ÍÂèÒ¡ÅÑÇ·Õè¨ÐÅéÁ"...ÍÒ¨ÒÃÂìÍӹǠ¢¹Ñ¹ä·Â ¤ÃÑé§áá㹪ÕÇÔµ·ÕèÊͺ¤³ÔµÊÁÒ¤Á¤³ÔµÈÒʵÃìàÁ×èÍ»Õ2533...¼Áä´éá¤è24¤Ðá¹¹(¨Ò¡ÃéͤÐá¹¹) 10 Á¡ÃÒ¤Á 2015 15:52 : ¢éͤÇÒÁ¹Õé¶Ù¡á¡éä¢áÅéÇ 2 ¤ÃÑé§, ¤ÃÑé§ÅèÒÊØ´â´Â¤Ø³ ¡ÔµµÔ |
#5
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ÍéÒ§ÍÔ§:
»Å.¶éÒàÃÒäÁè¼Ô´ ¡çãËé¤Ô´ÇèÒ⨷Âì¼Ô´¤ÃѺ 10 Á¡ÃÒ¤Á 2015 15:15 : ¢éͤÇÒÁ¹Õé¶Ù¡á¡éä¢áÅéÇ 1 ¤ÃÑé§, ¤ÃÑé§ÅèÒÊØ´â´Â¤Ø³ Aquila |
#6
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⨷Âì¤ÅéÒ ¡Ê¾·.»ÕÅèÒÊØ´¢éÍ15 ÁÒ¡¤ÃѺ áµèµÃ§ sin(2B) à»ç¹ sin(B) ¤ÃѺ
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#7
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⨷Âìà»ç¹áºº¹Õé¤ÃѺ ¢é͹Õé§èÒÂ
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#8
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à¤Â·ÓáÅéÇ áÅéÇ¡çÅ×Áä»áÅéÇ â¨·ÂìµÒÁ¤Ø³yellow ¤§àºÒ¢Öé¹à»ç¹¡Í§ à¾Ôè§à©ÅÂãËéÅÙ¡ä»
à»ÅÕè¹ $\cos B\rightarrow \sin A$ $\sin B\rightarrow \cos A$ áÅéÇ¡ÃШÒÂµÃ§æ ¨Ðä´é $\sin 3A=\frac{1}{2} $ àÍÒä»ÇÒ´ÊÒÁàËÅÕèÂÁ ËÒä´éÇèÒ $\tan 3A=\frac{1}{\sqrt{3} } $
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"¶éÒàÃÒÅéÁºèÍÂæ ã¹·ÕèÊØ´àÃÒ¨ÐÃÙéÇèÒ¶éÒ¨ÐÅéÁ ÅéÁ·èÒä˹¨Ðà¨çº¹éÍ·ÕèÊØ´ áÅÐÃÙéÍÕ¡ÇèÒµèÍä»·ÓÂѧ䧨ÐäÁèãËéÅéÁÍÕ¡ ´Ñ§¹Ñ鹨§ÍÂèÒ¡ÅÑÇ·Õè¨ÐÅéÁ"...ÍÒ¨ÒÃÂìÍӹǠ¢¹Ñ¹ä·Â ¤ÃÑé§áá㹪ÕÇÔµ·ÕèÊͺ¤³ÔµÊÁÒ¤Á¤³ÔµÈÒʵÃìàÁ×èÍ»Õ2533...¼Áä´éá¤è24¤Ðá¹¹(¨Ò¡ÃéͤÐá¹¹) |
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