九年级下册数学,求解救. (1)COS60°-COS45°+tan45°, (2)cos²60°+sin
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九年级下册数学,求解救. (1)COS60°-COS45°+tan45°, (2)cos²60°+sin²45°,
根据条件求锐角。
(1)sinA=0.753,求角A
(2)cosB=0.0832,求∠B
(3)tanC=45.8求∠C
根据条件求锐角。
(1)sinA=0.753,求角A
(2)cosB=0.0832,求∠B
(3)tanC=45.8求∠C
(1)COS60°-COS45°+tan45°,
=1/2-√2/2+1
=(3-√2)/2
(2)cos²60°+sin²45°,
=(1/2)²+(√2/2)²
=1/4+2/4
=3/4
再问: cos30°-sin45°/sin60°-cos45°,
再答: (cos30°-sin45°)/(sin60°-cos45°) =[cos(90°-30°)-sin(90°-45°)]/(sin60°-cos45°) =(sin60°-cos45°)/(sin60°-cos45°) =1
再问: (1)sinA=0.753,求角A (2)cosB=0.0832,求∠B (3)tanC=45.8求∠C
再答: (1)sinA=0.753, ∠A=48.85°或∠A=131.15° (2)cosB=0.0832, ∠B=85.23° (3)tanC=45.8 ∠C=88.75°
再答: 不谢
=1/2-√2/2+1
=(3-√2)/2
(2)cos²60°+sin²45°,
=(1/2)²+(√2/2)²
=1/4+2/4
=3/4
再问: cos30°-sin45°/sin60°-cos45°,
再答: (cos30°-sin45°)/(sin60°-cos45°) =[cos(90°-30°)-sin(90°-45°)]/(sin60°-cos45°) =(sin60°-cos45°)/(sin60°-cos45°) =1
再问: (1)sinA=0.753,求角A (2)cosB=0.0832,求∠B (3)tanC=45.8求∠C
再答: (1)sinA=0.753, ∠A=48.85°或∠A=131.15° (2)cosB=0.0832, ∠B=85.23° (3)tanC=45.8 ∠C=88.75°
再答: 不谢
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