化简sin(25π/12)cos(11π/6)-cos(11π/12)sin(5π/6)的值是
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化简sin(25π/12)cos(11π/6)-cos(11π/12)sin(5π/6)的值是
化简sin(25π/12)cos(11π/6)-cos(11π/12)sin(5π/6)的值是
化简sin(25π/12)cos(11π/6)-cos(11π/12)sin(5π/6)的值是
sin(25π/12)cos(11π/6)-cos(11π/12)sin(5π/6)
=sin(2π+π/12)cos(2π-π/6)-cos(π-π/12)sin(π-π/6)
=sin(π/12)cos(π/6)+cos(π/12)sin(π/6)
=sin(π/12+π/6)
=sin(π/4)
=√2/2
原式=sin(π/12)cosπ/6+cos(π/12)sinπ/6
=sin(π/12+π/6)
=sinπ/4=√2/2
sin(25π/12)cos(11π/6)-cos(11π/12)sin(5π/6)
=sin(2π+π/12)cos(2π-π/6)-cos(π-π/12)sin(π-π/6)
=sin(π/12)cos(π/6)+cos(π/12)sin(π/6)
=1/2[sin(π/12+π/6)+sin(π/12-π/6)]+1/2[sin(π/12+π/6)-...
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sin(25π/12)cos(11π/6)-cos(11π/12)sin(5π/6)
=sin(2π+π/12)cos(2π-π/6)-cos(π-π/12)sin(π-π/6)
=sin(π/12)cos(π/6)+cos(π/12)sin(π/6)
=1/2[sin(π/12+π/6)+sin(π/12-π/6)]+1/2[sin(π/12+π/6)-sin(π/12-π/6)]
=1/2[2sin(π/12+π/6)]
=sin(π/12+π/6)
=sin(3π/12)
=sin(π/4)
=√2/2
收起
原式=sin(25π/12-2π)cos(11π/6-2π)-[-cos(π-11π/12)]sin(π-5π/6)
=sin(π/12)cos(-π/6)+cos(π/12)sin(π/6)
=sin(π/12)cos(π/6)+cos(π/12)sin(π/6)
=sin(π/12+π/6)
=sin(π/4)
=√2/2