图
(cot120度+3cos315度)/(tan210度-sec225度)
=(-cot60度+3cos45度)/(tan30度+1/cos45度)
=(-√3/3+3√2/2)/(√3/3+√2)
=(9√2-2√3)/6X3/(√3+3√2)
=(9√2-2√3)/2(√3+3√2)
√3/2
解析:
sin(-300°)
=sin(-300°+360°)
=sin(60°)
=√3/2
~~~~~~~~~
tan(660°)
=tan(660°-720°)
=tan(-60°)
=-tan60°
=-√3