sin2x,cos2x,tan2x·Ö±ðÊǶàÉÙ?

sin2x=2sinxcosx¡£cos2x=(cosx)^2-(sinx)^2=2(cosx)^2-1=1-2(sinx)^2¡£tan2x=2tanx/(1-(tanx)^2)¡£±¶½Ç¹«Ê½£¬ÊÇÈý½Çº¯ÊýÖзÇ...


ÊýѧÈý½Çº¯Êý»»Ëãsin 2x = cos 2x = µÈµÈ»»Ë㹫ʽ...

sin 2x = 2sinxcosxcos2x=cosx^2-sinx^2.


sin2x+cos2xÔõô»¯¼ò - °Ù¶È¾­Ñé

2 Ê×ÏÈÔÚ¿Õ°×µÄÖ½ÉÏдÏÂÎÒÃǵÄËãʽ 3 ÀûÓòð·Ö¹«Ê½ÎÒÃÇ¿ÉÒԵõ½Ëãʽ=¡Ì2[(¡Ì2/2)sin2x+(¡Ì2/2)cos2x]4 ÔÙ½«¡Ì2/2±ä»»ÎªÈý½Çº¯ÊýÐÎʽ£¬µÃµ½¡Ì...


ΪʲôSin2xµÄµ¼ÊýÊÇ2cos2x¶ø²»ÊÇcos2x?

\sin2xÍâ²ãº¯ÊýΪy=\sin t,Äڲ㺯ÊýΪt=2x£¬\\¸ù¾ÝÁ´Ê½·¨Ôò£º\\\frac{dy}{dx}=\frac{dy}{dt}\cdot\frac{dt}{dx}=\cos t\cdot2=...


cos2xÓësin2xµÄ¹ØÏµÊÇʲô?

"cos2x"ºÍ"sin2x"ÊÇÈý½Çº¯ÊýÖеÄÓàÏÒºÍÕýÏÒº¯Êý£¬µ±Á½¸ö½Ç¶ÈÖ®¼ä´æÔÚÒ»¶¨¹ØÏµÊ±£¬ÕâÁ½¸öº¯Êý»áÓÐÌØ¶¨µÄ¹ØÏµ¡£¾ßÌåÀ´Ëµ£¬Í¨¹ýÈý½ÇºãµÈʽ¿ÉÒԵóöÒÔϹØÏµ£º cos2x = 1 ...


Èý½Çº¯ÊýÖÐcos2x,sin2x¡­µÈ¹«Ê½ÊÇ?

= (cosx)^2 - (sinx)^2 = 2(cosx)^2 - 1 = 1 - 2(sinx)^2sin2x = 2sinxcosxcos2X=(cosX)^2-(sinX)^2=2*(cosX)^2-1=1-2*(sinX)^2sin2x=2...


Ϊʲôsin2xµÄµ¼ÊýÊÇ2cos2x?

Ϊʲôsin2xµÄµ¼ÊýÊÇ2cos2x£¿ÕâÊǸö¸´ºÏº¯Êýร¬ÐèÒªÔËÓø´ºÏº¯ÊýÇóµ¼·¨Ôò¡£¿Éд³Éf(g(x)), ÆäÖÐ f(u)=sin u, g(x)=2x.Òò´Ë£¬Çóµ¼Íê...


Çóº¯Êýy=sin2x - cos2xµÄ×î´óÖµºÍ×îСֵ.

½â´ð:½â:¡ßy=sin2x-cos2x=2(22sin2x-22cos2x)=2sin(2x-¦Ð4),¡àµ±sin(2x-¦Ð4)=1ʱ,ymax=2,µ±sin(2x-¦Ð4)=-1ʱ,ymin=-2.


¹òÇó¡Òcos2x/sin^2xcos^2xdx Ê®Íò»ð¼±!

sin^2xcos^2x=1/4(2sinxcosx)^2=1/4sin2xԭʽ=¡Òcos2x/sin^2xcos^2xdx=¡Òcos2x/(1/4sin2x)dx=¡Ò2/sin2xd(sin2x)=2lnsin2x+C


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