sin²120°+cos180°+tan45°-cos²330°+sin(-210°)急用,注意 是cos²330°

sin²120°+cos180°+tan45°-cos²330°+sin(-210°)急用,注意 是cos²330°
sin²120°+cos180°+tan45°-cos²330°+sin(-210°)
急用,注意 是cos²330°

sin²120°+cos180°+tan45°-cos²330°+sin(-210°)急用,注意 是cos²330°

sin120°=sin60°=√3/2
cos180° = -1
tan45°=1
cos330° = cos30° = √3/2
sin(-210°) = sin(-360°+150°)=sin150°=sin30°=1/2
原式=3/4 -1 + 1 - 3/4 + 1/2 = 1/2

sin²120°+cos180°+tan45°-cos²330°+sin(-210°)
=3/4-1+1-3/4+1/2
=1/2

3/4-1+1-3/4+1/2=1/2

sin²120°+cos180°+tan45°-cos²330°+sin(-210°)
(sin60°)²-cos(0°)+tan45°-(cos30°)²+sin(30°)
=3/4+（-1）+1-3/4+1/2
=1/2

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