sin3xÇó¼«ÏÞÔõô×ö

limsin3x(xÇ÷ÏòÓÚ0)=0 limsin3x(xÇ÷ÏòÓÚÒ»¸öÊý£¬ÈôÕâ¸öÊýΪa)=sin3a limsin3x(xÇ÷ÏòÓÚÎÞÇî)¡ª¡ªÕâ¸öÊÇ·¢É¢µÄûÓм«ÏÞ


sin3xÔõôÇó¼«ÏÞ?

½â·¨Ò»£ºµÈ¼ÛÎÞÇîС lim sin3x/tan5x x¡ú0 =lim 3x/(5x)x¡ú0 =3/5 ½â·¨¶þ£ºÂå±Ø´ï·¨Ôò lim sin3x/tan5x x¡ú0 =lim 3cos3x/5sec²5x x¡ú0 =3...


µ±X¡ú0ʱ, sin3xÊÇ2xµÄ¼¸·ÖÖ®¼¸±¶¡£

=lim(x¡ú0)(3cos3x)/(2)=3/2 ¼´µ±x¡ú0ʱ£¬(sin3x)/2x=3/2£¬¼´sin3x=3/2*(2x)¡£ËùÒÔµ±X¡ú0ʱ£¬sin3xÊÇ2xµÄ3/2±¶¡£


lim sin3x/tan5xÔÚx - >paiʱµÄ¼«ÏÞΪʲô¿ÉÒÔÓÃÂå±Ø´ï...

¿ÉÒÔÓÃÂå±Ø´ï·¨ÔòÊÇ0/0ËùÒÔ=lim(3sec²3x/5cos5x)=3*1/[5*(-1)]=-3/5


lim sin3x/sin2xµÄ½âÌâ¹ý³Ì¼°½á¹û!x¡ú0

sin3x/sin2x=sin(2x+x)/sin2x=(sin2xcosx+cos2xsinx)/sin2x=sin2xcosx/sin2x + cos2xsinx/(2sinxcosx)=cosx + [2(cosx)^2-1]/(2cosx)=cosx + cosx -


¸ßÊýÈëÃÅÌâÇó½Ì¡£xÇ÷ÏòÓÚ3¦Ð,limsin3xΪʲôÊÇ0

x¡ú3¦Ð 3x¡ú9¦Ð sin9¦Ð=0 ¸ù¾ÝÁ¬ÐøÐÔ¼´¿É¡£


limx¡úTT sin3x ·ÖºÅ tan5x

ÏÔÈ»(sin3x)'=3cos3x£¬(tan5x)'=5/(cos5x)²Ô­¼«ÏÞ =lim(x->¦Ð) 3cos3x / [5/(cos5x)²]=lim(x->¦Ð) 0.6cos3x * (cos5x)²Õâ...


Çó¼«ÏÞlimxÇ÷½üÓÚ0sin3x³ýÒÔtan5x

¾ßÌåÀ´Ëµ£¬µ±xÇ÷ÓÚ0ʱ£¬sin3x¿ÉÒÔ½üËÆΪ3x£¬tan5x¿ÉÒÔ½üËÆΪ5x¡£Òò´Ë£¬Ô­Ê¼µÄ¼«ÏÞ±í´ïʽ¿ÉÒÔ¼ò»¯Îªlim sin3x/tan5x=lim 3x/5x=3/5¡£ÁíÒ»ÖÖÇó½â·½Ê½ÊÇÀûÓÃÂޱȴï...


.. lim sin3x x¡ú0 - - - =1 sin2x

Ôò2xºÍ3xÇ÷ÓÚ0 ËùÒÔsin3x/3xºÍsin2x/2x¼«ÏÞ¶¼µÈÓÚ1 sin3x/sin2x=[3*(sin3x/3x)]/[2*sin2x/2x)]=3/2*[(sin3x/3x)]/[sin2x/2x)]ËùÒÔ¼«ÏÞ=3/2 ...


sin3X/tan5X,X¡úÅÉ,ÓÃÂå±Ø´ï·¨ÔòÇóÏÂÁм«ÏÞ

·½·¨1¡¢limsin3X/tan5X=limsin3xcos5x/sin5x=lim(1/2)(sin8x-sin2x)/sin5x(»ý»¯ºÍ²î)=lim(1/2)(8cos8x-2cos2x)/5cos5x(·Ö×Ó·ÖĸͬʱÇóµ¼)=(1/2)(8...


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