sin690°Xsin150°+cos930°Xcos( -270°)+tan120°Xtan1050°求解!

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sin690°Xsin150°+cos930°Xcos( -270°)+tan120°Xtan1050°求解!
sin690°Xsin150°+cos930°Xcos( -270°)+tan120°Xtan1050°求解!

sin690°Xsin150°+cos930°Xcos( -270°)+tan120°Xtan1050°求解!
sin690°Xsin150°+cos930°Xcos( -270°)+tan120°Xtan1050°
=sin(720-30)Xsin(180-30)°+cos(720+180+30)°Xcos( -270°)-tan60°Xtan(1080-30)°
=SIN30SIN30-COS30COS(-90)+TAN60TAN30
=1/4-0+1
=5/4

原式= -(sin30°)^2 + (cos30°)^2 + (tan60°)^2
=-(1/4)+(3/4)+3
=3.5

原式=sin(-30)°Xsin(-30)°-cos30°X0+tan(-60°)Xtan(30°)
=1/4-0+1=5/4