sin2 840°+cos540°+tan225°-cos2(-330°)+sin(-210°)解题步骤和答案!

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sin2 840°+cos540°+tan225°-cos2(-330°)+sin(-210°)解题步骤和答案!
sin2 840°+cos540°+tan225°-cos2(-330°)+sin(-210°)解题步骤和答案!

sin2 840°+cos540°+tan225°-cos2(-330°)+sin(-210°)解题步骤和答案!
sin^2840°+cos540°+tan225°-cos2(-330°)+sin(-210°)
=sin^2(900°-60°)+cos(360°+180°)+tan(180°+45°)-cos2(-360°+30°)-sin(180+30°)
=-sin^2(-60°)-1+1-3/4+1/2
=-3/4-1+1-3/4+1/2
=-1