#1
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¡Ó˹´ãËé an à»ç¹ÅӴѺàâҤ³Ôµ â´Â·Õè a1=sinx , a2=cosx, a3=tanx àÁ×èÍ x à»ç¹¨Ó¹Ç¹¨ÃÔ§
¤èÒ n ã¹¢éÍã´µèÍ仹Õé·Õè·ÓãËé an= 1+cosx ¡.4 ¢.5 ¤.6 §.7 ¨.8 ¢Íº¤Ø³¤ÃѺº |
#2
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$a_1a_3=a_2^2$
$\frac{\sin^2x}{\cos x} =\cos^2 x$ $\sin^2x-\cos^3x=0$ $\cos^3x+\cos^2x-1=0 $ 仵èÍäÁèä´éáÅéÇ
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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) |
#3
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¼ÁµÔ´àËÁ×͹¤Ø³¡ÔµµÔàŤÃѺ
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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. |
#4
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仵èÍä´éÊÔ¤ÃѺ ¨Ñ´´Õæ Áѹ¨Ðä´é $a_{n}=\frac{1}{\cos^2 x}$
àÊÃç¨áÅéÇãªé $\cos ^3x=\sin ^2x$ àÍÒä»äÅè¡Ñº $a_{n}=a_{1}r^{n-1}$ (àÅ×Í¡ $r=\frac{\cos x}{\sin x}$) á¡éÊÁ¡ÒÃä´é $n=8$ |
#5
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àÍèÍÍ §§ÍèÒ¤ÃѺº ú¡Ç¹¢ÍÅÐàÍÕ´˹èÍÂä´éÁÑé¤ÃѺº
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#6
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¨Ñ´ÃÙ» $\cos ^3x+\cos ^2x-1=0$ â§à¢éÒËÒ $a_{n}=1+\cos x$
áÅéÇ¡çàÍÒ $\cos ^3x=\sin ^2x$ ä»ËÒ $n$ ¨Ò¡ $a_{n}=a_{1}r^{n-1}$ |
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