解
sin(29/6π)
=sin(4π+5π/6)
=sin(5π/6)
=sin(π-π/6)
=sin(π/6)
=1/2
cos(31/4π)
=cos(8π-π/4)
=cos(-π/4)
=cosπ/4
=√2/2
tan(-1560)
=-tan(1560)
=-tan(180×9-60)
=-tan(-60)
=tan(60)
=√3