#1
|
||||
|
||||
µÃÕ⡳ÁÔµÔ
à»ç¹â¨·Âì·Õè¼ÁÅͧµÑ駢Öé¹ÁÒàÅè¹æ´ÙÍФѺ¼Ô´¾ÅÒ´µÃ§ä˹ºÍ¡´éǹФѺ
1.¶éÒ$cos2+cos4+cos6+...+cos88$ä´éà·èҡѺà·èÒäà 2.ªÒ¤¹Ë¹Öè§Â×¹º¹Ë¹éÒ¼ÒÁͧÁÒÂѧ¶¹¹ÊÒÂ˹Öè§àËç¹ËÅÑ¡äÁÅìà»ç¹ÁØÁ¡éÁ 45 ͧÈÒ ààÅÐ 22 ͧÈÒ µÒÁÅӴѺ¨§ËÒÇèÒ˹éÒ¼ÒÊÙ§à·èÒäÃ(¡Ó˹´ãËécot 22=1.473)(¢é͹Õé¼Á¤Ô´ä´é 1 ÍèҤѺààµè¼ÁÇèÒäÁè¹èÒ¨Ðãªè) 3.¢éÍã´µèÍ仹ÕéÁÕ¤èÒà·èҡѺ $sin^4A+cos^4A$ ¡.$sin^2A+cos^2A$ ¢.$1-sin^2A cos^2A$ ¤.$1-cos^4A$ §.$-2sin^2A cos^2A$
__________________
¤¹àÃÒËÒ¡ÅéÁ¡çµéͧÅØ¡ ¼Ùéã´ÅéÁààÅéÇäÁèÅØ¡¼Ùé¹Ñé¹ÂÔ觡ÇèÒÊعѢ ÊعѢÁѹÅéÁààÅéÇÁѹÂѧÅØ¡ä´é ààÅéÇ·ÓäÁ¤¹¶Ö§¨ÐÅØ¡äÁèä´é |
#2
|
|||
|
|||
¢éÍ 3 ¼ÁµÍº § «Öè§ã¡Åéà¤Õ§·ÕèÊØ´à¾ÃÒмÁä´é = $1-2cos^2Asin^2A$
¢éÍ 1 ¹Ô¹èÒ¨ÐÁÕ ¡ÓÅѧ 2 ¹Ð¤ÃѺ ¶éÒäÁèÁÕ¡çËÒ¡ÃШÒÂàŤÃѺ Êèǹ¢éÍ 2 ¹Õé¼ÁäÁèá¹èã¨ÇèÒ⨷Âì¤ÃºÃÖ»èÒÇà¾ÃÒÐäÁèä´é¤ÇÒÁËèÒ§¨Ò¡ËÅÑ¡äÁÅìä»Âѧ˹éÒ¼Ò¨Ö§ËÒ¤ÇÒÁÊÙ§äÁèä´é(ËÃ×ͼÁäÁèÁÕ¤ÇÒÁÊÒÁÒö¾Í) |
#3
|
||||
|
||||
¢éÍ 1 ¼ÁäÁèá¹èã¨ÇèÒ⨷Âì¼Ô´ ËÃ×ͼÁ¤Ô´äÁèä´éàͧ¹Ð¤ÃѺ à¾ÃÒÐẺ¹Õ餧µéͧ¡ÃШÒÂÍÂèÒ§à´ÕÂÇ - -
¢éÍ 2 ÂѧäÁèä´é·Ó (¾ÔÁ¾ì·ÓäÁà¹Õè 55+) ¢éÍ 3 ¼Á¡çä´é àËÁ×͹¡Ñº ¤Ø³ PoSh ¤ÃѺ $sin^4A + cos^4A$ $= (sin^2A)(sin^2A) + (cos^2A)(cos^2A)$ $= (1-cos^2A)(sin^2A) + (1-sin^2A)(cos^2A)$ $= sin^2A+cos^2A-sin^2Acos^2A-sin^2Acos^2A$ $= 1-2sin^2Acos^2A$ |
#4
|
||||
|
||||
àËç¹´éǤÃѺ
¶éÒà»ç¹¡ÓÅѧ2¡ç¨Ðãªé⤿ѧªÑè¹µèͤÃѺ
__________________
100 ¤¹¤Ô´ 10 ¤¹·Ó 1 ¤¹ÊÓàÃç¨ 24 ÁÕ¹Ò¤Á 2009 17:28 : ¢éͤÇÒÁ¹Õé¶Ù¡á¡éä¢áÅéÇ 3 ¤ÃÑé§, ¤ÃÑé§ÅèÒÊØ´â´Â¤Ø³ {ChelseA} |
#5
|
||||
|
||||
¶éÒ¡¡ÓÅѧÊͧ¡çãªé $Sin^2+Cos^A=1$ áÅÐ $CosA=Sin(90-A)$ ¨Ðä´é 22 ËÃ×Í»èÒǤÃѺ
__________________
à˹×Í¿éÒÂѧÁÕ¿éÒáµèà˹×Í¢éÒµéͧäÁèÁÕã¤Ã »Õ¡¢Õé¼×駢ͧ»ÅÍÁ§Ñé¹ÊԹР...âÅ¡¹ÕéâË´ÃéÒ¨ÃÔ§æ ÁѹãËé¤ÇÒÁÊØ¢¡ÑºàÃÒ áÅéÇÊØ´·éÒ Áѹ¡çàÍҤ׹ä»... |
#6
|
||||
|
||||
µÍº22 ¤ÃѺ à¾ÃÒШѺä´é22¤Ùè ¤ÙèÅÐ1
|
#7
|
||||
|
||||
COS˹ԵéͧÁÕ Í§ÈÒ µÒÁ´éÇÂÍèÐà»ÅèÒÍèÐ:
__________________
24 ÁÕ¹Ò¤Á 2009 20:47 : ¢éͤÇÒÁ¹Õé¶Ù¡á¡éä¢áÅéÇ 1 ¤ÃÑé§, ¤ÃÑé§ÅèÒÊØ´â´Â¤Ø³ ¤usÑ¡¤³Ôm |
#8
|
||||
|
||||
¶éÒãªéàÍ¡Åѡɳì $cos(A+B) = cosAcosB-sinAsinB$ ÍÒ¨¨ÐÍÍ¡ÁÒÇÂæ¡çä´é¤ÃѺ
|
#9
|
|||
|
|||
ÍéÒ§ÍÔ§:
¼ÁËÒáÅéÇä´é 22˹èÇ |
#10
|
||||
|
||||
ÍèÒ¤ÃѺ
ààÅéǵ¡Å§µéͧÁÕ¡ÓÅѧÊͧËÃ×Í»èÒǤÃѺ ËÃ×ÍÇèÒäÁèÁÕ¡çËÒä´é¤ÃѺ µÍ¹¹Õé¡ç¡ÓÅѧÁÖ¹æÍÂØèàËÁ×͹¡Ñ¹¤ÃѺ
__________________
¤¹àÃÒËÒ¡ÅéÁ¡çµéͧÅØ¡ ¼Ùéã´ÅéÁààÅéÇäÁèÅØ¡¼Ùé¹Ñé¹ÂÔ觡ÇèÒÊعѢ ÊعѢÁѹÅéÁààÅéÇÁѹÂѧÅØ¡ä´é ààÅéÇ·ÓäÁ¤¹¶Ö§¨ÐÅØ¡äÁèä´é |
|
|