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Cos²60°+sin²60°答案

cos²60°+sin²60°=1

cos²60° +sin²60° =(2分之1)²+(2分之根号3)² =4分之1+4分之3 =1 很高兴为您解答,祝你学习进步! 如果我的回答对你有帮助,请及时选为满意答案,谢谢~~

(1)sin45°-cos60°+tan60°=√2/2-1/2+√3 (2)cos²30°+sin²30°-tan45°=3/4+1/4-1=0 (3)sin30°-tan30°+cos45°=1/2-√3/3+√2/2 (4)cos30°-sin45°/sin60°-cos45°=√3/2-(√2/2)/(√3/2)-√2/2=√3/2-√6/3-√2/2 (5)sin²30°+2sin60°+t...

∵60°<α<150° ∴90°

(sinA)^2=(1/2)(cos(B-C)-cos(B加C))=(1/2)(cos(B-C)加cosA),A=60,将A正弦余弦代入,得cos(B-C)=1,B=C=60度 (2)由正弦定理,a^2=bc,由余弦a^2=b^2加c^2-2bccosA,得cosA=(a^2加b^2-1)/2>(2bc-1)/2=1/2,所以sinA最大为(根号3)/2,S=0.5bcsi...

1²+(✔3/3)²=4/3=(2✔3/3)² 原式提取因数2✔3/3后得: 原式=2✔3/3(✔3/2cosα+1/2sinα) =2✔3/3(sin60°cosα+cos60°sinα) =2√3/3sin(60°+α)

sin45=cos45 所以原式=(cos60+cos45)/(cos60-cos45)+(cos60-cos45)/(cos60+cos45) =(cos²60+2cos60cos45+cos²45+cos²60-2cos60cos45+cos²45)/(cos²60-cos²45) =2(cos²60+cos²45)/(cos²60-cos²...

=√2x√3/2-4x3/4+√2/2x√3 =√6-3

sin²B+cos²(150°-B) =(1-cos2B)/2+[1+cos(300°-2B)]/2 =1+[cos(60°+2B)-cos2B]/2 =1-sin(30°+2B)sin30° =1-1/2sin(30°+2B) 显然B=30°时上式有最小值1/2. 请采纳,谢谢!

1)2sin²60°-√3tan30°-2cos²45° =2(√3/2)²-√3×*√3/3-2(√2/2)² =3/2-1-1 =-1/2 2)√2×sin45°+√3×cos30°-3/2 =√2×√2/2+√3×√3/2-3/2 =1+3/2-3/2 =1 -2三次方 × 2负一次方 +根号12 除以 (tan30°-cos45°) =-8×1/2+√12/(√3/3-√2/...

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