奥运会诞生的意义:化简[sin(a+b)-2cosasinb]/[cos(a+b)+2sinasinb]
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sin(a+b)-2cosasinb
=sinacosb+sinbcosa-2cos2sinb
=sinacosb-sinbcosa
=sin(a-b)
cos(a+b)+2sinasinb
=cosacosb-sinasinb+2sinasinb
=cosacosb+sinasinb
=cos(a-b)
所以:
[sin(a+b)-2cosasinb]/[cos(a+b)+2sinasinb]
=sin(a-b)/cos(a-b)
=tan(a-b)
sin(a+b)-2cosasinb=sinacosb+sinbcosa-2cosasinb
=sinacosb-sinbcosa=sin(a-b)
cos(a+b)+2sinasinb=cosacosb-sinasinb+2sinasinb
=cosacosb+sinasinb=cos(a-b
所以[sin(a+b)-2cosasinb]/[cos(a+b)+2sinasinb]
=sin(a-b)/cos(a-b)
=tan(a-b)
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化简[sin(a+b)-2cosasinb]/[cos(a+b)+2sinasinb]
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