sin4xcos4x
y=sin4xcos4x ÇóT
sin4xcos4x=1/2 * sin8x ËùÒÔT=2pi/8=pi/4
ÒÑÖªy=sin4x+cos4x,Çóy(n)
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ÒÑÖªº¯Êýf(x)=sin4x+cos4x(×¢:ÒòΪÎÒ²»»á´ò4´Î·½,Æäʵ...
f(x)=(sinx)^4+(cosx)^4f(x)=[(sinx)^2+(cosx)^2]^2-2(sinx)^2(cosx)^2f(x)=1-(sin2x)/2-1
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sin4x=2 sin2x cos2x=2 sinx cosx(1-(sinx)^2)cos4x=[1-(sin2x)^2]/2=[1-4(sinx)^2 (cosx)^2]/2±¶½Ç¹«Ê½Ö»Òª¼Çס¶þ±¶½Ç¾ÍºÃ,¸ß±¶µÄÓöþ±¶½Ç¹«Ê½½µ½×...
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sin4x+cos4x
sin4x+cos4x =cos4x+sin4x =¡Ì2(cos4x¡Ì2/2+sin4x¡Ì2/2)=¡Ì2(cos4xcos¦Ð/4+sin4xsin¦Ð/4)=¡Ì2cos(4x-¦Ð/4)»¹¿ÉÒÔת»¯ ¡Ì2sin(4x+¦Ð/4)=¡Ì2sin(¦Ð...
ÒÑÖªº¯Êýf(x)=sin4xcos4x,Ôòf(x)µÄÖÜÆÚÊÇ
f(x)=sin4xcos4x =1/2*sin8x T=2¦Ð/8=¦Ð/4
ÇóÖ¤sin^4x+cos^4x=1 - 2sin^2xcos^2x
ÇóÖ¤sin^4x+cos^4x=1-2sin^2xcos^2xÖ¤:sin^4x+cos^4x=(sin^2x+cos^2x)^2-2sin^2xcos^2x=1-2sin^2xcos^2x
½«f(x)=sinËĴη½+cosËĴη½»¯³É±ê×¼Èý½Çº¯Êý
=1-1/2*sin2x =1-1/2*(1-cos4x)/2 =1/4*cos4x+3/4½âÎö¿´²»¶®?Ãâ·Ñ²é¿´Í¬ÀàÌâÊÓÆµ½âÎö²é¿´½â´ðÏàËÆÎÊÌâ Èý½Çº¯ÊýÌâ ÒÑÖªsin¦Á=¸ùºÅ5·ÖÖ®5,ÔòsinµÄ4´Î·½¦Á-cosµÄ...
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