作业帮cos40°+sin50°×(1+√3cot10°)
来源：学生作业帮 编辑：拍题作业网作业帮 分类：数学作业 时间：2024/04/30 16:53:39
cos40°+sin50°×(1+√3cot10°)
最好能讲讲怎么做这类题?
[cos40°+sin50°×(1+√3cot80°)]/sin70°×√1+sin50°
最好能讲讲怎么做这类题?
[cos40°+sin50°×(1+√3cot80°)]/sin70°×√1+sin50°
先化简分子：
1+√3cot80°=1+√3tan10°
=(cos10°+√3sin10°)/cos10°
=2(1/2cos10°+√3/2sin10°)/cos10°
=2(sin30°cos10°+cos30°sin10°)/cos10°
=2sin40°/cos10°
故cos40°+sin50°×(1+√3cot80°)
=cos40°+2sin50°sin40°/cos10°
=cos40°+2sin50°cos50°/cos10°
=cos40°+sin100°/cos10°
=cos40°+1
=2cos²20°
分母sin70°×√1+sin50°
=sin70°×√(sin²25°+2sin25°cos25°+cos²25°)
=sin70°×√(sin25°+cos25°)²
=sin70°(sin25°+cos25°)
=√2(cos45°sin25°+sin45°cos25°)sin70°
=√2sin70°sin70°
=√2sin²70°
=√2cos²70°
故原式=2/√2=√2
1+√3cot80°=1+√3tan10°
=(cos10°+√3sin10°)/cos10°
=2(1/2cos10°+√3/2sin10°)/cos10°
=2(sin30°cos10°+cos30°sin10°)/cos10°
=2sin40°/cos10°
故cos40°+sin50°×(1+√3cot80°)
=cos40°+2sin50°sin40°/cos10°
=cos40°+2sin50°cos50°/cos10°
=cos40°+sin100°/cos10°
=cos40°+1
=2cos²20°
分母sin70°×√1+sin50°
=sin70°×√(sin²25°+2sin25°cos25°+cos²25°)
=sin70°×√(sin25°+cos25°)²
=sin70°(sin25°+cos25°)
=√2(cos45°sin25°+sin45°cos25°)sin70°
=√2sin70°sin70°
=√2sin²70°
=√2cos²70°
故原式=2/√2=√2
cos40°+sin50°×(1+√3cot10°)
[cos40°+sin50°(1+√3tan10°)]/[sin70°√(1+cos40°)]=
(cos40°+sin50°(1+√3tan10°))/sin70°√(1+cos40°)
[cos40°+sin50°(1+√3tan10°)]/[sin70°√(1+cos40°)]=?
『cos40°+sin50°（1+√3tan10°）』/sin70°√1+cos40°』
求值：cos40°+sin50°(1+3tan10°)sin70°1+sin50°
求值{cos40°+sin50°(1+根号3tan10°)}/1+sin50°
化简sin50°+cos40°(1+√3tan10°)/sin^270°
sin10°sin50°为什么等于1/2(cos40-cos60)
为什么sin50°=cos40°
请问sin50°是不是等于cos40°,cos40等于sin50,sin10等于cos80
化简：[sin50°+cos40°(1+根号3tan10°)]/sin²70°