[2sin50+sin80(1+根号3*tan10)]/根号(1+cos10)急!

来源:学生作业帮助网 编辑:作业帮 时间:2024/05/04 15:22:51
[2sin50+sin80(1+根号3*tan10)]/根号(1+cos10)急!

[2sin50+sin80(1+根号3*tan10)]/根号(1+cos10)急!
[2sin50+sin80(1+根号3*tan10)]/根号(1+cos10)
急!

[2sin50+sin80(1+根号3*tan10)]/根号(1+cos10)急!
[2sin50°+sin80°(1+(√3)tan10°)]∕√(1+cos10°)
√(1+cos10°)必定是化为√[1+2(cos5)^2-1]=√2·cos5
sin80°(1+(√3)tan10°)=cos10(1+(√3)tan10°)
=2(cos10/2+根号3/2sin10)
=2sin40
分子:[2sin50°+sin80°(1+(√3)tan10°)]
=2(sin50+sin40)
=2(sin50+cos50)
=2·根号2sin95=2·根号2cos5
分母是√2·cos5
那么原式的值是2

2sin50+sin80(1+根号3*tan10)]/根号(1+cos10)
=2sin50°+cos10°(1+根号3*tan10°)]/根号(1+cos10°)
=[2sin50°+(cos10°+√3sin10°)]/√(1+cos10°)
=[2sin50°+2sin(10°+30°)]/(√2*cos5°)
=2√2sin(50°+45°)/(√2*cos5°)
=2√2sin95°/(√2*cos5°)=2