»¯¼ò: sin40¡ã(tan10¡ã - tan60¡ã)

=sin40¡ã(tan10¡ã-¸ùºÅ3)=sin40*sin10/cos10-¸ùºÅ3*sin40 =sin40*cos80/cos10-¸ùºÅ3*sin40 =sin40*cos80/2sin40*cos40-¸ùºÅ3*sin40 =(1/2)*cos80/cos...


Ò»µÀÊýѧÌâ,×îºÃдϹý³Ì:sin40'(tan10'¼õ¸ùºÅ3)<'±íʾµ¥...

=sin40'*(tan10'-tan60')=sin40'*(sin10'cos60'-sin60'cos10')/(cos10'cos60')=-sin40'sin50'/(cos10'cos60')=-2sin40'cos40'/cos10'=-sin80'/si...


sin40¡ã(tan10¡ã - ¡Ì3)=?

tan10-¡Ì3=sin10/cos10-¡Ì3=(sin10-¡Ì3cos10)/cos10=2sin(10-60)/cos10=-2sin50/cos10sin40(tan10-¡Ì3)=-(2sin40sin50)/cos10=-[cos(50-40)-cos(50...


...¡Ì3/(cos 10¡ã);(2) sin 40¡ã(tan 10¡ã - ¡Ì3).

(1) 1/(sin 10¡ã)-¡Ì3/(cos 10¡ã)=(cos 10¡ã-¡Ì3sin 10¡ã)/sin 10¡ã*cos 10¡ã=2(1/2cos 10¡ã-¡Ì3/2sin 10¡ã)/sin 10¡ã*cos 10¡ã=2sin (30¡ã-...


...30¡ã¡¢60¡ã¡¢45¡ã µÄ cos¡¢tan¡¢sin ËټǼ¼ÇÉ,²¢ÇÒ...

¸÷ÖµµÄ²ÎÊýÈçÉϱí¸ñ tan90¡ã=ÎÞÇî´ó £¨ÒòΪsin90¡ã=1 £¬cos90¡ã=0 £¬1/0ÎÞÇî´ó £©£»cot0¡ã=ÎÞÇî´óÒ²ÊÇͬÀí¡£À©Õ¹×ÊÁÏ ¹ØÓÚsinµÄ¶¨Àí...


Çósin40¡ã(tan10¡ã - ¸ùºÅ3)µÄÖµ

sin40¡ã£¨tan10¡ã-¸ùºÅ3£©=sin40¡ã(sin10¡ã/cos10¡ã-¸ùºÅ3)=sin40¡ã£¨sin10¡ã-¸ùºÅ3cos10¡ã)/cos10¡ã=2sin40¡ãsin(10¡ã-60¡ã)/cos10¡ã =-2sin40¡ãcos40...


»¯¼ò: sin40¡ã(tan10¡ã 3 ) = - - - .

sin40¡ã(tan10¡ã−3)=sin40¡ã£¨sin10¡ãcos10¡ã−3£©=sin40¡ã•sin10−3cos10¡ãcos10¡ã=2sin40¡ã(12sin10¡ã−32cos10¡ã)cos10...


Ôõô²»¼ÆËãÖ±½Ó»¯¼òtan(10)/[tan(20)tan(40)],µ¥Î»ÊÇ...

sin160¡ã/sin20¡ã=1/8ËùÒÔÓÐtan10¡ã/(tan20¡ãtan40¡ã)=cot20¡ãcot40¡ãcot80¡ã=1/(8sin20¡ãsin40¡ãsin80¡ã)=-1/(4(1/2-cos20...


...cos10(¸ùºÅ3tan20 - 1)3.sin50(1+¸ùºÅ3tan10)4.sin40...

1 ԭʽ=(cos10-¸ùºÅ3*sin10)/(1/2)*2sin10cos10=4sin(30-10)/sin20=42 ԭʽ=tan70*cos10*(¸ùºÅ3sin20/cos20-1)=tan70*cos10*2sin(-10)/cos20=tan70...


ÈçºÎ¼òµ¥µØËã³ö4sin40¡ã - tan40¡ãµÄÖµ?

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